The Impact of Joint Child Custody Policies on Children’s Long-Term Outcomes

Alexandra Rohde April 20, 2016

Faculty Thesis Advisors: Professor Prakarsh Singh and Professor Caroline Theoharides

Faculty Readers: Professor Adam Honig and Professor Daniel Barbezat

Submitted to the Department of Economics at Amherst College in partial fulfillment of the requirements for the degree of Bachelor of Arts with honors.

Abstract

Since the 1970s, almost all US states have introduced laws allowing for joint child custody. This move towards joint custody has strengthened in recent years, with states increasingly considering laws that would establish a presumption that joint custody is in the best interests of the child. However, there is little evidence to either support or rebut the contention that joint custody leads to better outcomes for children. In this paper, I work to fill this void by assessing the long-run implications for children of growing up exposed to joint custody legislation. I first employ two separate national datasets to show that enactment of joint custody laws increased the prevalence of actual joint custody arrangements. I then use decennial censuses from 1990 to 2010 to examine the effects of these laws on children’s long-term outcomes. I find that exposure to joint custody laws and practices as a youth has a negative effect on educational attainment. In particular, exposure to joint custody decreases the likelihood that a person will obtain a high school degree. My results imply that, at best, joint custody can have no effect on children’s outcomes and, at worst, can harm long-term educational achievement.

JEL Classification: I00, I30, J01, J12, J13, J16, J18, K00, K36

Key words: Health, Education, and Welfare; Microeconomics; Law and Economics

Acknowledgements

I thank Professor Prakarsh Singh and Professor Caroline Theoharides for their invaluable help advising this project. I thank Professor Jessica Reyes for serving as the fearless leader of our thesis seminar and a preliminary adviser to this thesis. I thank Juan Montecino for his help with

STATA and Andy Anderson for his help with ArcGIS, the software used to create the maps I present. In addition, I thank the many professors who have inspired, mentored and encouraged me throughout my four years at Amherst, including but not limited to professors Danielle

Benedetto, Lisa Brooks, William Pritchard and Stanislav Rabinovich. I thank my good friends

Steven, Tierney, Cristian and Claire for making me laugh and smile always. Finally, I thank my siblings Stefanie, Julia and Daniel, mother Louise and boyfriend Tommy for keeping me sane and happy during this process.

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PART I. INTRODUCTION ...... 2 PART II. BACKGROUND: THE LAW OF JOINT CUSTODY ...... 5 II.A. CODING OF THE JOINT CUSTODY LAWS ...... 7 II.B. NO-FAULT DIVORCE LAWS ...... 9 PART III. THEORETICAL CONSIDERATIONS ...... 10 PART IV. DO JOINT CUSTODY LAWS PREDICT JOINT CUSTODY ARRANGEMENTS? ...... 18 PART IV.A. TESTING USING VITAL STATISTICS ...... 18 PART IV.B. TESTING USING CPS ...... 24 PART V. THE DYNAMICS OF JOINT CUSTODY ARRANGEMENTS ...... 33 PART VI. THE LONG-TERM EFFECTS OF JOINT CUSTODY LAWS ON CHILDREN ...... 40 PART VI.A. CENSUS DATA ...... 40 PART VI.B. VARIATION IN EXPOSURE TO DIVORCE AND CUSTODY LAWS ...... 41 PART VI.C. IDENTIFICATION STRATEGY ...... 43 PART VI.D. RESULTS ...... 47 PART VI.E. EXPLORING EFFECTS BY GENDER ...... 51 PART VII. ADDITIONAL ROBUSTNESS CHECKS ...... 54 PART VII.A. ROBUSTNESS CHECK FOR MIGRATION ...... 54 PART VII.B. ROBUSTNESS CHECK FOR ADULT EXPOSURE...... 55 PART VIII. CONCLUSION ...... 55 REFERENCES ...... 58 APPENDIX ...... 60

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Part I. Introduction

The American family has undergone dramatic changes over the last few decades.

Marriage rates have fallen, cohabitation has emerged as an important social practice, and divorce rates have soared.1 This transformation of the American family has developed as women have made large gains in economic independence and as family law has undergone drastic changes, including the introduction of no-fault divorce laws and the increasing popularity of joint custody arrangements for children of divorce.

These changes have caused alarm, largely because of their perceived negative consequences for children. This reaction may not be unwarranted, as an extensive body of research documents that children of divorce have greater psychological and social problems, both as children and as adults (Amato and Keith 1992; Keith and Finley 1988; Amato and Keith

1991).

However, there are a number of issues in using this body of evidence to draw a causal link between divorce and child outcomes. First, divorce is not an exogenous event with respect to other determinants of child outcomes. Certain families are more likely to divorce, and the qualities that predict divorce can also predict child outcomes. Second, these studies often overlook the nuances of post-divorce arrangements, including the custody arrangements of divorced (or otherwise estranged) families. Over the past four decades, there have been significant changes to the laws that govern these arrangements. In particular, beginning in the late 1970s, states began adopting laws that explicitly allowed or encouraged joint custody arrangements. Since most marriages involve children, the assignment of child custody in marital dissolution is an overlooked and likely important factor in divorce trends. Buchanan, Maccoby,

1 Divorce rates rose over 200% between the mid-1960s and the early 1980s (Gruber 2000). 3 and Dornbusch (1996) succinctly classify the factors affecting children’s post-divorce adjustment into three categories: loss of a parent, inter-parental conflict, and diminished quality of parenting.

Families’ custody arrangements affect all three of these categories. Ongoing and frequent access to both parents may mitigate potential effects of parental absence as seen in sole-custody households, and access to the resources and guidance of both parents may reduce economic and psychological stress and disadvantage for the child. On the other hand, however, ongoing contact with both parents might strain family resources and expose the child to ongoing conflict, thereby exacerbating the negative effects of divorce.

Much attention has been devoted to studying the effects of divorce and divorce law on children. Yet, despite the close relationship between custody and divorce, much less attention has been dedicated to studying the effects of joint custody arrangements and the effects of joint custody laws on children.2 Yet understanding the dynamics of joint custody laws and joint custody arrangements is of critical importance for our society. Approximately 35% percent of all children live without at least one biological parent (Child Trends 2015). And, despite an only rudimentary understanding of the effects of current joint custody laws, lawmakers in many states are proposing new forms of legislation that further encourage joint custody agreements. For example, lawmakers in approximately 20 states are currently considering laws that would that mandate that, except in cases involving physical or substance abuse, both parents have an equal

50-50 split of time with children.3 Before expanding any such laws, it is crucial that we understand the effects of the laws already in place. This paper is an attempt to do just that.

2 Most of what we currently know about child custody comes from studies by legal scholars (such as Maccoby and Mnookin 1997). The body of economic literature on this subject is small, though it is growing. Researchers have examined parental rates of labor force participation (Altindag, Nunley and Seals 2013), marriage (Halla 2009), divorce (Allen and Brinig 2011; Allen and Brinig 2000; Brinig and Buckley 1998), child-support receipts (Allen, Nunley and Seals 2008; Weiss and Willis 1985) child investment (Nunley and Seals, 2011, Rasul 2006), and short- term educational attainment (Leo 2006). 3 For examples of specific laws, see Cordell (2015). 4

My basic strategy to estimate the effects of joint custody on long-term outcomes is to utilize the variation associated with the timing of the enactment of the laws supporting joint custody across the states. Because this variation is not at the individual level, it resolves the sample selection problems of earlier studies. This approach is similar to the one used by Gruber

(2000) to study the effects of unilateral divorce on long-term outcomes.

Before delving into the effect of joint custody laws, I perform a number of related but separate analyses. First, I gather the limited data available on joint custody to show that the joint custody laws actually affect the prevalence of joint custody arrangements. Next, I use a novel data set to compute the prevalence of joint custody by state and year, which I label “joint custody practices.” I use this measure of joint custody exposure—which also varies only by state and year—as a further test of the effects of joint custody on long-term outcomes. Third, I explore some of the channels through which joint custody might affect children. In particular, I examine the effects of divorce laws, custody laws, and actual custody practices on child support payments and on contact with parents. Fourth and finally, I use the information on the timing of joint custody laws and practices across the states to examine the impact of joint custody on the long- term outcomes of children of divorce.

The paper proceeds as follows. In Part II, I provide background on custody laws and the movement towards joint custody arrangements. In Part III, I go through the Coase Theorem and other theoretical considerations. In Part IV, I use two sets of data to determine whether joint custody laws predict joint custody arrangements. In Part V, I discuss the short-term effects of actual joint custody arrangements. In Part VI, I discuss some of the long-term effects of youth exposure to joint custody laws and practices. In Part VII, I discuss a few additional checks for robustness. In Part VIII, I conclude. 5

Part II. Background: The Law of Joint Custody

After a divorce, child custody has traditionally been granted to only one parent. Who that parent might be has changed over time. Before the nineteenth century, custody was usually awarded to the father, even when he had caused the marriage to end. In nineteenth-century

America, however, this began to change. Courts started awarding custody to the mother when the father was at fault, on the theory that the children would be “best taken care of and instructed by the innocent party” (Kelly 1994). In most cases, this meant that custody was awarded to mothers.

No-fault divorces were not then available, and divorcing fathers usually admitted fault to procure the divorce (Kelly 1994).

In the twentieth century, the focus of custody decisions shifted from parental fault to the interests of the child. As a result, custody continued to be awarded to mothers, but now because the “tender years” doctrine began to take hold, in which young children—children of “tender years”—were thought to need a mother more than they needed a father. Therefore, when a child was very young, mothers were usually granted custody (Kelly 1994).

Over time, divorce laws again shifted, moving from the “tender years” doctrine to the

“best interests of the child” doctrine. This “best interests of the child” standard initially resulted in a continued presumption of maternal custody. However, around the 1960s and 1970s, the strength of this presumption began to dissipate, spurred by protests by fathers’ rights groups and some feminist organizations. Soon, judges began ruling that policies that favored mothers in the case of divorce violated the 14th Amendment’s guarantee of equal protection under the law. In the benchmark case, Watts v. Watts, in 1973, Judge Kooper of the Family Court of New York ruled that any presumptive preference in favor of maternal custody violated the father’s right to 6 equal protection. This ruling was corroborated by other changes in family law. For instance, six years after Watts v. Watts decision, the Supreme Court held in Orr v. Orr that sex-based custody preferences in determinations of alimony were unconstitutional.4 As a result of these changes, courts came to aim directly at the best interest of the child, without applying any presumptions about which parent should get custody (Brinig and Buckley 1998). Beginning in 1973, states began introducing laws that either favored or explicitly allowed joint custody, thus increasing divorced fathers’ access to and authority over their children (Brinig and Buckley 1998). Over the next two decades, joint custody laws spread to nearly all fifty states.5

Importantly, many of these laws did not differentiate between legal joint custody agreements and physical joint custody agreements, though there are large differences between the two. Custody agreements generally specify arrangements for both forms of custody for children below 18. In sole physical custody arrangements, a child lives mainly with one parent, although the child may spend substantial time with the non-resident parent through visitation provisions. Joint physical custody means that the child will spend substantial, but not necessarily equal, proportions of residential time with both parents. Joint legal custody refers to the expectation that there will be substantial shared decision making between parents concerning the child's education, health care, extracurricular activities, and religion. Thus joint custody can entail joint legal custody, joint physical custody, or both joint legal and joint physical custody.

However, joint physical custody is typically more difficult to obtain, and, even in those cases in which joint physical custody is granted, this arrangement rarely results in an equal sharing of parenting time (DiFonzo, Pezzuti, Guliano and Rivkin 2013).6

4 440 U.S. 268 (1979) 5 See Table 1 for a list of the states with joint custody laws and the years in which those laws were introduced. 6 In fact, many states are like Missouri, which defines joint custody as “awarding each of the parents significant, but not necessarily equal” time with the child (DiFonzo, Pezzuti, Guliano and Rivkin 2013). 7

II.A. Coding of the Joint Custody Laws

As the above section indicates, there is much ambiguity about exactly what constitutes joint custody.7 Thus different scholars record the changes in custody laws in different ways. To document the availability of joint custody in each state, I follow Brinig and Buckley (1998), updated by Halla (2009). The authors define states with joint custody laws as those that mention joint custody as an option, since courts in all such states appear ready to grant joint custody.

Where the statute does not refer to joint custody as an option, but reported cases support such awards, the state is considered a joint custody state. Two aspects of these laws are worth emphasizing. First, joint custody can constitute joint legal custody or joint physical custody. If either is mentioned, then the state is coded as a joint custody state. Second, a state is coded as a joint custody state if joint custody is explicitly allowed. Thus a state need not encourage joint custody to be considered a joint custody state. My coding of joint custody laws is listed in

Appendix Table 1 and depicted graphically in Figure 1. Examining the map in Figure 1 shows that no systematic geographical patterns in the adoption of joint custody laws are observable.

This further supports my strategy that the differential timing of joint custody reforms provides a useful quasi-experiment to study the causal effect of joint custody on children.

I find that Indiana was the first state to implement joint custody laws in 1973, followed by New Hampshire in 1974. Arkansas was the latest state to implement joint custody laws in

2003. Currently Washington and West Virginia are the only two states that still have not implemented joint custody laws.

7 See DiFonzo, Pezzuti, Guliano and Rivkin (2013) for an in-depth discussion of this ambiguity. 8

Figure 1 Enactment of Joint Custody Laws by State

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II.B. No-Fault Divorce Laws

Adding to the overall ambiguity is the change in a different but related law around this period. Under a decade before many states began adopting joint custody laws, many states experienced a “divorce revolution.” Prior to 1969, spouses typically either had to wait for a long period of time or had to prove that a fault such as adultery or abuse had been committed in order to obtain a divorce. Beginning in 1969, however, states began enacting legal reforms that simplified legal difficulties in obtaining a divorce. In particular, states began adopting no-fault divorce laws, which allowed couples to obtain a divorce without having to establish fault as a principle. Instead, spouses could claim “irreconcilable differences” or “incompatibility” as reasons for a divorce. These laws enabled one spouse to unilaterally end a marriage without demonstrating specific fault-based grounds.8 By the late 1970s, the majority of states changed their laws to allow for no-fault divorce. These laws were considered a routine policy refinement when introduced but have become incredibly politicized, largely because their introduction corresponded with a dramatic increase in the divorce rate.9

Unlike joint custody laws, no-fault divorce laws have received a lot of attention in the literature. This paper does not intend to add to that body of literature. However, because of the close relationship between children, divorce, and custody arrangements, as well as the proximity

8 During the same period, about half the states also adopted specific no-fault rules for property division and spousal divorce (Mechoulan 2006). 9 The literature remains inconclusive on the causal link between the reforms and the jump in the divorce rate. Gruber (2000) uses Census data to conclude that the stock of divorced people rose significantly in no-fault divorce states. However, research by Wolfers (2006) reveals that, while the stock of the currently divorced may have risen, the probability of being ever-divorced is little changed by no-fault divorce laws. Friedberg (1998) notes that the flow of new divorces does in fact rise following a shift to no-fault divorce laws, though Wolfers (2006) shows that these effects are transitory and fade out within a decade. One possible reconciliation of these results is that no-fault divorce leads to earlier divorce and less remarriage, a result confirmed by Rasul (2006). 10 in timing of these two legal movements, I include no-fault laws as a control in my empirical work below.10

Part III. Theoretical Considerations

The Coase Theorem

The first step in determining the effect of joint custody laws on children is assessing whether or not the laws increased the number of children with joint custody arrangements. This is a hotly contested question. Since the publication of Becker’s A Treatise on the Family (1981), there has been an ongoing debate over whether legal institutions and the laws they create affect family behavior. The foundation of this debate is the Coase Theorem, which stipulates that, if property rights are complete and parties can negotiate costlessly, then changes in these property rights should not affect the outcome of the negotiation.

Viewed in a Coasian framework, the shift to joint child custody laws constitutes a shift in the initial allocation of property rights. Prior to the introduction of joint custody laws, the initial property right to custody of the child in the case of divorce generally belonged to the mother.

Joint custody laws, however, shifted property rights such that each parent had an equal right to shared custody in the case of divorce. The Coase Theorem suggests that, as long as property rights remain clearly defined, then changes in these property rights—in this case, changes in custody law—should not affect the incidence of joint custody. However, the Coase Theorem predicts that changes in custody law will affect the compensation scheme used to obtain a joint custody arrangement.

Research indicates that, when there is a disagreement between the parents about custody, it is usually because mothers want sole custody and fathers want joint custody (Mnookin and

10 I use the coding of no-fault laws from Mechoulan (2006). My coding of these laws by state is listed in Appendix Table 1 and shown graphically in Appendix Figure 1. 11

Maccoby 1992). If this is the case for a particular family, then the Coase Theorem suggests that, if the father’s gain from joint custody is greater than the mother’s loss, then joint custody will occur.11 However, in order to gain joint custody when the mother does not have to agree to it

(when there are not joint custody laws), the father will have to compensate the mother. Joint custody laws alter this process of compensation. In the absence of joint custody laws, the mother does not have to compensate the father in order to get sole custody, and she must be compensated for the father to get joint custody. Once joint custody laws are in place, however, the mother loses bargaining power. This is the case regardless of the custody outcome. If she gains more than the husband loses by having sole custody, she will negotiate to get joint custody, but she will have to compensate the father to do so. If the husband gains more than she loses by having a joint custody agreement, then they will have a joint custody agreement. Unlike before, however, the mother will not be compensated.

This is an interesting exercise. If we assume the conditions of the Coase Theorem are met, then the answer to the question I posit is no, joint custody laws should not increase the incidence of joint custody agreements. However, in demonstrating how joint custody arrangements will not increase, this exercise provides a separate possible channel through which kids can be affected by these laws: by diminishing mothers’ resources. The mother may not get keep the family home or she may receive less alimony or child support. Thus the laws may have a wealth transfer effect.

11 To carry out this theoretical analysis, I make three simplifying assumptions. First, I assume that joint custody is allowed whether or not there is a joint custody law, so couples can bargain around the allocation of custody. This makes sense because, before the introduction of joint custody laws, joint custody was not illegal, but it was very rare. Second, I assume that if a parent wants joint custody after a state adopts joint custody laws, then he/she can get it without having to obtain the agreement of his/her spouse. Third and finally, I assume that if two parents bargain and agree to a certain custody agreement, then the judge will respect the parents’ wishes and grant the agreed-upon arrangement. 12

My focus in this paper is on children. Since the wealth is being transferred from one parent to the other, this wealth transfer effect does not necessarily imply that there will be any effect on the child. However, there are reasons to suspect that the reduction in mother’s resources will have more negative effects on children than the offsetting increase in father’s resources.

First, divorced mothers tend to have much lower income than divorced fathers, so the marginal utility of the income is likely to be higher (Brinig and Buckley 2000). Second, as noted by

Gruber (2000), there is a large literature suggesting that mothers are more likely than fathers to devote resources to children.

Thus, when examining the long-term effects of the adoption of joint custody laws on children, the Coase Theorem does not provide straightforward predictions. However, one implication of the Coase Theorem is clear: the introduction of joint custody laws should not affect the rate of joint custody agreements. I test this implication in Part IV. If the Coase

Theorem holds, I should find no increase. However, the Coase Theorem does not predict that I will find no result in my main regression, in which I test the effects of being exposed as a youth to joint custody laws on long-term educational outcomes (Part V). This is due to the existence of the wealth transfer effect I identify above. The Coase Theorem predicts that mothers in joint custody states will have fewer resources than those in states without joint custody laws. Since mothers are often the primary caregivers (even under joint custody agreements) and since financial resources are critical to long-term success and educational attainment, then the Coase

Theorem implies that changes in custody laws will change long-term outcomes.

If I do find an increase in joint custody rates after the adoption of joint custody laws, all hope is not lost. There are many reasons to suspect that the Coase Theorem may not apply. The

Coase Theorem states that if 1) property rights are complete and 2) parties can negotiate 13 costlessly, then the parties will always negotiate an efficient solution. In the case of custody agreements, it is likely that neither condition is fully met. First, property rights are not necessarily complete. Before joint custody laws were implemented, we assume that the property right to custody of the child belonged to the mother, and thus the father had to compensate the mother to negotiate a joint custody agreement. After joint custody laws were implemented, we assume that the property right is shared equally between the two parents, so that, if no parent compensates the other, then parents will share custody of the child.

However, neither of these assumptions is necessarily satisfied in instances of parents bargaining over custody arrangements. This is largely because the negotiation over custody, as well as the negotiation over divorce, necessarily involves a third party, be that a judge or a legal mediator. In divorces involving children, the judge that grants a couple its divorce generally also grants the couple its custody arrangement. Thus, for example, if a couple in a state without joint custody laws negotiates and decides to share custody, the judge has the power to ignore the parents’ wishes and grant a sole custody arrangement instead.12 The possibility that a judge may deny an agreed-upon custody arrangement diminishes the incentives for parents to negotiate over the arrangement, thus creating the possibility that parents will simply allow the judge to determine the custody arrangement even if a certain type of custody arrangement maximizes both parents’ utility.

The issue of the existence of the judge also illustrates why the second criterion for the

Coase Theorem may not be satisfied: that bargaining will not be costless. Assume that a judge in a state without joint custody laws can usually be persuaded to award parents joint custody if they have a good lawyer, constructed a full parenting plan and demonstrated that they are fit parents

12 Theoretically the couple could ignore the judge’s ruling and renegotiate privately after the custody arrangement is determined, but evading the law could impose additional costs that violate the condition that bargaining is costless. 14 who can cooperate with each other. Completing all three of these tasks requires time and effort, making this negotiation costly. With joint custody laws, parents are required to jump through fewer hoops to obtain a custody arrangement, and therefore again the switch to joint custody laws may change actual custody arrangements.

Third and finally, evidence from behavioral economics indicates that people may not always negotiate in fully rational manner, and that people may be heavily influenced by the status quo (Sunstein, Jolls and Thaler 1998). Changes in institutions, including laws and general attitudes, can change people’s perspectives and can change how parents evaluate alternatives. In the case of joint custody, although joint custody has always existed (it has never been illegal), it was extremely rare before the early 1980s. Before then, it might not have even occurred to fathers to try to bargain over it. Thus, joint custody laws could affect the incidence of joint custody agreements, not because couples previously could not bargain over custody arrangements, but rather because couples did not bargain over custody arrangements, even if doing so would be Pareto improving.

In summary, the Coase Theorem predicts that joint custody laws will not affect the incidence of joint custody, but these laws may still have effects on children due to changes in the bargaining relationships between parents. In addition, if the Coase Theorem does not apply, then these laws can also affect children by changing the incidence of joint custody.

How Joint Custody Arrangements Directly Affect Children

If joint custody laws do lead to an increase in joint custody arrangements, then the effect of the laws on children will depend in part on the effect of joint custody itself on children’s outcomes. There are several possible channels through which joint custody can affect children’s 15 outcomes. First, joint custody can affect the emotional health of children. Joint custody came into favor in large part because of its potential to reduce the trauma that children experienced during divorce. Proponents of joint custody contend that these arrangements can diminish the extent to which children feel they are “losing” a parent during divorce and these arrangements can prevent the non-resident parent from being viewed as merely a “visitor” to his or her child.

To the extent that joint custody fosters continued close relationships with both parents, joint custody likely improves the emotional health of children.

Of course, joint custody arrangements can also affect the emotional health of children in a negative way. The primary risk is adding additional instability in children’s lives—children with joint physical arrangements no longer have one home, but two. This risk intensifies depending on the degree of animosity between parents. As demonstrated in a later section, joint custody almost always entails legal joint custody. Legal custody means that parents have to agree on all important decisions concerning the children. The court system is littered with cases in which divorced parents with joint legal custody have to keep re-litigating every aspect of their children’s upbringing—whether it is whether the children go to church or attend private school.

With joint physical custody, parents have to coordinate even more: they have to work together to monitor homework, decide on discipline, and be in constant communication. To the extent that conflict between parents is bad for children, joint custody can serve to simply to prolong that conflict beyond the date of divorce. According to Robert Emery, professor of psychology at the

University of Virginia, “In low or controlled conflict divorces, children fare better in joint than in sole physical custody. In high conflict divorces, children do worse in joint physical custody than in other arrangements” (Emery 2009). 16

Second, joint custody can affect the financial resources devoted to children. Again, this effect can be positive or negative. Brinig and Buckley (1998) use bonding theory to explain how parents change their behavior and invest more in their children in response to the introduction of joint custody laws. The authors posit that joint custody laws assuage fathers’ fears of being completely separated from their children in the case of divorce, which increases fathers’ commitment to their children during marriage. Allen, Nunley and Seals (2011) corroborate this hypothesis. Using Panel Study of Income Dynamics (PSID) data, the authors find that married mothers allocate more time to market work and married fathers allocate more time to household work in response to joint-custody reforms. Similarly, Brinig and Buckley employ monitoring theories to analyze how joint custody addresses an agency-cost problem that arises under sole custody. Under sole custody agreements, the noncustodial parent cannot easily see how his financial contributions are spent, and therefore assumes the risk that some money will be misspent. Through joint custody, the parent can monitor for such problems. With joint legal custody, the parent has increased responsibility and decision-making authority. With joint physical custody, the parent has increased access to the child and can monitor and regulate the child’s spending of money directly. Thus, parents with either form of joint arrangement may more willingly invest in their children with joint custody.

On the negative side, joint custody can simply drain family resources, thus leaving less money to be invested in children. With joint physical custody, both parents need to have enough space for their child to live with them comfortably, requiring total investment in housing to be larger than with sole physical custody. This may not be a hardship for families with resources large enough that the additional expenses are not significant, but for families with fewer resources, higher housing costs can significantly reduce living standards. Increasing financial 17 stress on families can have significant adverse outcomes on children: Not only are they affected directly by the lower resources—a poorer diet, lower quality schools, less opportunity for enrichment—but greater financial stress can also reduce parenting quality.

Third and finally, joint custody can affect the quality of parenting available to children of divorce. One benefit provided by joint custody is that it diminishes some of the inefficiencies typically associated with divorce in families with children. Within a marriage or cohabitation, time enjoyed with children could be shared. But prior to the advent of joint custody, time spent with children became, as Allen and Brinig (2011) eloquently put it, “lumpy.”13 Custody options were few—mostly sole custody to the mother or sometimes to the father—with visitation every other weekend and perhaps one night a week, or not. This lumpiness can often impose a deadweight loss and can therefore be welfare-reducing. Take, for example, a family with a father who works full-time and a mother who works part-time. In the case of divorce, the mother would likely want the children to live with her for a good part of the time, but she may not object to having a 60-40 split with joint physical custody. Thus, the introduction of joint custody could benefit the mother too, and possibly improve her quality of parenting.14 In essence, joint custody makes post-divorce arrangements more similar to pre-divorce arrangements, in which there were two parents who could split parenting responsibilities and take advantage of economies of scale

(two parents instead of one who could drive a child to soccer practice) and gains to specialization

(mom always helps with science homework; dad always helps with essays).

13 In the conflict literature, this lumpiness is often referred to as “issue indivisibility” (Fearon 1995). 14 Welsh-Osga (1981) found that shared custody parents were less overburdened by parenting responsibilities than sole custody parents. This difference among custody arrangements is exemplified by the finding by Pearson and Thoennes (1990, pg. 139) that 40 percent of parents with sole maternal, 25 to 30 percent of sole paternal or joint legal, and only 13 percent of parents with shared custody agreed with the statement "I often feel overwhelmed by the amount of time and energy my children require." 18

Because of the many channels through which joint custody can affect children, the question of how children are affected overall is a priori unclear. In addition, there are likely differential effects by family. For families for whom the loss of income is important and for those families who are more prone to parental conflict, the imposition of joint custody may pose large risks to children’s long-term outcomes.

Part IV. Do Joint Custody Laws Predict Joint Custody Arrangements?

Before determining the long-term effect of joint custody laws, I test the most obvious channel through which joint custody laws could affect kids: whether or not joint custody laws affect actual joint custody arrangements. The Coase Theorem suggests that they do not. If they do, however, this provides an important channel through which the laws might affect children’s outcomes in the long-run. To test the existence of this channel, I use two separate data sets to test the effects of laws on custody: Vital Statistics, which has the advantage of being very large but covers only 19 states for at most six years, and the April Child Support Supplement to the CPS, a much smaller data set but one that covers all states over a much longer period of time.

Part IV.A. Testing Using Vital Statistics

Between 1989 and 1995, the National Center for Health Statistics (NCHS) gathered information on physical (and only physical) custody arrangements as part of the Divorce Data

Set within the Vital Statistics program.15 NCHS did so by compiling counts from records of registered divorces maintained by 19 state government departments.16 The data include all records for participating states with small numbers of events and a sample of records for

15 National Center for Health and Human Services (1997), accessed through National Bureau of Economic Research. 16 After 1995, the NCHS stopped producing the detailed divorce files due to a lack of funds. 19 participating states with larger numbers of events. All in all, the data set 893,770 observations,

285,380 of which concern divorces of couples with children.

There are four important limitations of this dataset. First, the data cover only six years,

1989 to 1995, and only 19 states (with only 15 states participating in all six years). Most of the covered states had already enacted joint custody laws by 1989, so there is not that much variation to exploit. Second, these data provide information only on custody arrangements of divorcing couples, and exclude those custody arrangements of parents who were never married, a category that includes cohabitating couples as well as couples that never lived together.17 The exclusion of never-married couples’ agreements will likely cause me to overestimate the proportion of couples with joint physical custody agreements, as never-married couples are less likely to formally share custody of the children.18 Finally, these data include information on only physical custody arrangements. Because legal joint custody arrangements are more popular than physical joint custody arrangements, this exclusion will cause me to underestimate the proportion of couples with some sort of joint custody arrangement. If joint custody laws encourage legal joint custody more strongly than they encourage physical joint custody, then this exclusion will cause me to underestimate the degree to which joint custody laws predict joint custody arrangements.

In my regressions, I include only cases in which either sole or joint custody is awarded, limiting my sample to 262,837 families. I exclude cases in which no custody was awarded, some

17 This excluded group is substantial. The proportion of births to unmarried women has increased greatly in recent decades, rising from 5% in 1960 to 32% to 1995 to 40% in 2014 (Child Trends 2015). 18 This is the case for two reasons. First, it is more difficult for never-married parents to share custody. Brooks-Gunn (2011) finds that one-half of unmarried parents are living together at the time of their child’s birth and only 35% of are still living together five years after the birth of the child. Second, it is much more difficult for a never-married biological father to be awarded any custody rights of his children. Though groups are currently fighting to change these laws, in many states the unmarried mother is presumed to have the primary or natural right to custody of children born. Often her rights are typically only defeated if the mother is proved unfit (Katz 1994). In addition, in some cases, never-married biological fathers have to fight to even be established as the legal father (Huntington 2015). 20 sort of combination custody was awarded, or custody was granted to a non-parent.19 Table 1 shows the summary statistics for this dataset once I limit my sample. The data suggest that, between 1989 and 1995, 24% of divorces involving children under 18 resulted in joint physical custody to both parents. In the remaining 76% of the observations, 68% resulted in sole custody to the mother and 9% resulted in sole custody to the father.

Table 1 Vital Statistics Summary Statistics N Mean SD Custody Arrangement Joint Custody Arrangement 262,837 0.24 0.43 Sole Custody Arrangement 262,837 0.76 0.43 Father Has Sole Custody of Children 262,837 0.09 0.28 Wife Has Sole Custody of Children 262,837 0.68 0.47

Number of Children under 18 262,837 1.78 0.88 Marriage Duration in Years 262,837 9.81 6.43

Spouses' Age at Decree Age of Wife 249,548 32.37 7.17 Age of Husband 250,453 34.95 7.83

Number of This Marriage Wife's No. 245,173 1.25 0.51 Husband's No. 245,048 1.27 0.53

Spouses' Race Only Wife is White 262,837 0.02 0.12 Only Husband White 262,837 0.01 0.12 Both Spouses are Non-White 262,837 0.24 0.43

Family Law Joint Custody Law at Time of Divorce 262,837 0.89 0.31 No-Fault Divorce Law at Time of Divorce 262,837 0.92 0.27 Both Laws at Time of Divorce 262,837 0.83 0.38 No. Years Joint Law in State Before Divorce 262,837 8.82 5.27

19 These categories combined constitute less than 8% of the total sample. 21

No. Years No-fault Law in State Before Divorce 262,837 17.30 9.73 No. Years Both Laws in State Before Divorce 262,837 8.47 5.61 Joint Law in State 1-5 Years Before Divorce 262,837 0.17 0.37 Joint Law in State 6 or More Years Before Divorce 262,837 0.73 0.44 Sources and Notes: These data are from the National Center for Health Statistics (1989-1995).

To test whether custody laws affect custody practices, I run a regression of joint physical custody on joint custody laws and individual demographics. Following Halla (2009), I control for a number of individual characteristics that are likely to affect custody determinations, including the number of children under 18, the duration of the marriage, the number of times each spouse has been married before, the race of each spouse, the age of each spouse, and whether each spouse is a resident of the state of divorce.

To test the effect of having a joint custody law in the state of divorce, I measure the effect of having a law that was implemented 1-5 years before the year of divorce and the effect of having a law that was implemented for 6 or more years at the time of divorce. I do this because laws often take time to go into effect, it takes time for citizens of a state to learn of a law change, and because part of the effect of these laws is changing attitudes for joint custody (for example, having a joint custody law might cause many to change their opinion on the feasibility of joint custody).20

Table 2A reports the results of these regressions. Each regression includes year fixed effects to account for changing attitudes towards joint custody over time, as well as fixed effects for the age of the husband and the age of the wife. The first column omits state of divorce effects; the second includes them. In both specifications, joint custody laws predict actual

20 I find almost identical effects if I categories are 1-4 years and 5 or more years, 1-6 years and 7 or more years, 1-7 years and 8 or more years, and 1-8 and 9 or more years. 22 custody arrangements. In the specification without state fixed effects, states that enacted joint custody laws six or more years prior to the divorce have an incidence of joint physical custody that is 13 percentage points higher than other states. With state fixed effects, having joint custody laws at the time of divorce also becomes significant, but the effects are diluted. Simply having a law raises the prevalence of joint custody arrangements by about 3 percentage points, while having joint custody laws for at least six years before the divorce increases the effect by 4.5 percentage points. Thus, the data suggest that joint custody is higher in states that have enacted joint custody laws and that the effect increases over time.21

Table 2B demonstrates empirically that the rise in joint custody agreements largely comes from a fall in sole custody agreements to the mother. Column (1) of Table 2B shows that, when state fixed effects are not included, the incidence of sole custody to the mother is 12.2 percentage points lower in states that enacted joint custody laws six or more years prior to the divorce. Column (2) shows that, when state fixed effects are included, the incidence of sole custody to the mother is almost 4 percentage points lower in these states. Thus joint custody laws are causing some divorcing families to substitute away from having the mother as the sole custodian to having both parents as equal custodians. Sole custody to the father also declines significantly in response to joint custody laws, but the magnitude of this decline is much smaller than that of mother’s sole custody, likely because sole custody to the father is unlikely in either regime, except in cases in which the mother is deemed unfit.

21 Because my dependent variable is binary, I run the same regressions with a probit model as a check for robustness, and I find that my results are robust to this check. See columns (3) – (4) in Table 10 in the Appendix for the results of the check. 23

Table 2A Do Custody Laws Predict Physical Custody Arrangements? Evidence from Vital Statistics Family Has Joint Physical Custody (1) (2)

1-5 Years of Joint Custody Law 0.01 0.025*** at Time of Divorce (.017) (.008) 6 + Years of Joint Custody Law 0.13*** 0.045** at Time of Divorce (.037) (.017)

Observations 238,706 238,706 R-squared 0.05 0.142 Year of Divorce FE X X State of Divorce FE X

Table 2B Do Custody Laws Cause Decreases in Sole Custody? Evidence from Vital Statistics

Mother Has Sole Custody Father Has Sole Custody (1) (2) (3) (4) 1-5 Years of Joint Custody Law -0.006 -0.021** -0.005 -0.004** at Time of Divorce (0.016) (0.008) (0.003) (0.002) 6 + Years of Joint Custody Law -0.122*** -0.039** -0.008* -0.005 at Time of Divorce (0.034) (0.016) (0.005) (0.003)

Observations 238,706 238,706 238,706 238,706 R-squared 0.055 0.117 0.028 0.033 Year of Divorce FE X X X X State of Divorce FE X X

Sources and Notes: These data are from the National Center for Health Statistics. The full set of control variables are those shown in Table 4. All regressions include wife and husband age fixed effects. Standard errors are corrected for clustering at the state of divorce level. I control for having no-fault divorce laws and for having both no-fault divorce laws and joint custody laws. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

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Part IV.B. Testing Using CPS

The Current Population Survey Child Support Supplement provides another very useful source of data on child custody arrangements. The Child Support Supplement is a biannual survey conducted as a follow-up telephone interview to the March Annual Social and Economic

Supplement. Survey respondents are asked if there is a child living in the household who has a parent living outside of the household. If so, the parent is asked a number of questions about the arrangements between that child and the other parent. In particular, beginning in 1994, respondents are asked whether “a court or judge” has ever given them physical or legal custody of their children.22 Since these questions were asked of everyone rather than only of those who had experienced a divorce, the CPS data capture some part of the resolution of custody in out-of- wedlock cases.23

Although the CPS supplements I rely on begin in 1994, they are retrospective in nature.

That is, they record the year in which a child support agreement was negotiated and in which the last divorce took place, allowing me to calculate joint custody decisions much earlier than 1994.

For example, if a parent in 1996 says she was divorced and awarded child support in 1985, I get an observation on joint custody awarded in 1985, even though the survey itself was taken in

1994.24 This previously-unexploited use of the CPS data provides (to my knowledge) the first national measure of physical and joint custody arrangements over time.

22Although the Child Support Supplement was first introduced in 1979, it was not until 1994 that it asked about physical custody. Furthermore, the supplement was changed substantially in 1994 in a manner such that earlier versions are not comparable to the later surveys. 23 Indeed, the data show that marital status affects custody outcomes: the most frequent custody arrangement for single mothers is full legal and sole custody, and unwed mothers are more likely to have sole custody arrangements than are mothers of divorce. 24 My procedure to choose the year custody is determined is as follows. When there is a child support agreement, I use the year of that agreement as the year of custody determination, as child support and custody are generally ruled on together, and can occur before, after, or at the same time of the divorce. Typically, when both are reported, divorce year and custody year are within one or two years of each other. When no such agreement exists, I use the year of divorce as the year of custody determination. This procedure is subject to some error, as the respondents 25

My data consist of all parents who report that their child has a parent living outside of the household. The parent answers the questionnaire for themselves and the children, so I pull all the parent’s pertinent information onto the children’ records, then drop all of the parents’ records and keep the information for only one child per household to avoid overweighting large households. My sample includes 29,178 families. Table 3 presents the summary statistics for this dataset. Only 23% of the families have some type of joint custody agreement: 11% have both legal and a physical joint custody agreement, 9% have only legal joint custody agreements, and

2% have only physical joint custody agreements. Thus, for most families, sharing physical custody also means sharing legal custody (but sharing legal custody does not necessarily mean sharing physical custody). The remaining families have either sole custody or no custody agreement at all.25

report only the parent of the children. I drop the few cases in which the year of divorce preceded the year of the birth of the child, but there is clearly some unavoidable measurement error relating to the year of custody determination. Furthermore, in many cases, no divorce or custody year is reported. 25 The data do not differentiate between those with no custody arrangement and those with sole custody arrangements. 26

Table 3: Summary Statistics for the CPS Std. Variable N Mean Dev. Family Characteristics No. Kids in Family 29,178 1.65 0.91 Age of Youngest Child 21,150 5.65 4.28 Child Under Three? 29,178 0.21 0.41 Residential Parent's Years of Education 27,864 12.69 2.44 Residential Parent White 28,225 0.70 0.46

Custody Agreement Has Only Legal Joint Custody Agreement 29,178 0.09 0.29 Has Only Physical Joint Custody Agreement 29,178 0.02 0.14 Has Both Physical and Legal Joint Custody 29,178 0.11 0.32 Has Either Physical or Legal Joint Custody 29,178 0.22 0.42

Family Dynamics Has Legal Child Support Agreement 29,178 0.51 0.50 Parent Received All Child Support Owed 9,187 0.67 0.47 No. Days Child Has Seen Non-Residential Parent within Last Year 20,558 76.03 92.86 Child Has Had Contact with Non-Custodial Parent within Last Year 27,712 0.74 0.44

Divorce and Custody Laws No-Fault Divorce Law at Time of Custody Agreement 29,178 0.87 0.34 Joint Custody Law at Time of Agreement 29,178 0.93 0.26 Both Laws at Time of Agreement 29,178 0.81 0.39 No. Years Unilateral Divorce in Place at Year of Custody Agreement 20,408 19.76 12.87 No. Years Joint Custody Law in Place at Year of Custody Agreement 20,408 13.18 8.07 No. Years Both Laws in Place at Year of Custody Agreement 20,408 10.91 8.97 1-5 Years of Joint Custody Laws at Time of Custody Agreement 29,178 0.86 0.35 6+ Years of Joint Custody Laws at Time of Custody Agreement 29,178 0.07 0.25

27

Figure 2A shows the national trends in joint custody and legal custody arrangements between 1978 and 2008.26 As expected, both forms of joint custody were very rare before 1980, but increased relatively steadily between then and 2006. Figure 2B depicts graphically the empirical result shown in Table 2B: the increase in joint custody arrangements corresponded to a fall in arrangements in which mothers had sole custody. These figures depict a few other important trends as well. First, Figure 2A demonstrates that joint physical arrangements are less common than joint legal arrangements. Since states’ joint custody laws typically do not differentiate between joint legal custody and joint physical custody, and since joint legal custody seems like it adds less instability to a child’s life, it is not surprising that judges demonstrate a preference for granting joint legal custody. Second, Figure 2A shows that neither type of joint arrangement occurs more than 30% of the time. Thus there has been a strong preference for sole custody arrangements since at least the 1970s, and Figure 2B shows that the most common arrangement is still sole custody to the mother. Third and finally, Figure 2A displays a dip in both forms of joint custody around 2006 and 2007, the period during which the Great Recession occurred, indicating that economic conditions affect family arrangements. One explanation for this phenomenon is that receiving a reward of joint custody often requires more time and money spent in court, and people had less disposable income during the recession.27

26 I show until only 2008 rather than 2010 because I use year of custody agreement for the year of the data and few respondents in 2010, the last year of my data, had actually had a custody agreement that year (as opposed to one in, for instance, 2007). 27 A number of papers find that the same relationship holds for divorce rates. For instance, Hellerstein and Morrill (2011) find that a one percentage point increase in the unemployment rate is associated with an approximately one percent fall in the divorce rate. However, much of this evidence is anecdotal. 28

Figure 2A: Families with Joint Figure 2B: Share of Sole Custody Custody Going to Mothers

30% 100% 95% 20% 90% 10% 85% 0% 80% 1979 1983 1987 1991 1995 1999 2003 2007 1979 1983 1987 1991 1995 1999 2003 2007 Year of Custody Agreement Year of Custody Agreement Legal Physical Physical Legal

Figure 2 Trends in Joint Custody Arrangements Sources and Notes: All data from IPUMS-CPS (1994-2010).

Do Joint Custody Laws Predict Joint Custody Practices in the CPS? The main drawback of the CPS data is that they have very few observations in the early years, when most states were just adopting child custody regulations. Most of the observations are from the late 1990s and early 2000s, when most states already had enacted joint custody laws. As a result, there is little variation in my laws: 93% of my sample had joint custody laws in their state at the time of custody agreement, and 86% had joint custody laws for six or more years at the time of custody agreement. I use this variation to test whether having a no-fault divorce law or a joint divorce law at the time of the custody arrangement affects the chance of actually receiving a joint custody agreement. I assume that the custody arrangement for family i living in state s with a custody agreement in year t is given by:

(1)

퐶푢푠푡표푑푦푖푡푠 =∝ + 훽1퐽표𝑖푛푡푙푎푤푈푛푑푒푟5푡푠 + 훽2퐽표𝑖푛푡푙푎푤6푃푙푢푠푡푠 + 훽3푁표푓푎푢푙푡푙푎푤푡푠 + 푋푖 + 휖푖푡푠

where Custody can be having a joint physical custody arrangement, having a joint legal custody arrangement, or receiving all the child support that is owed. 푋푖 represents a vector of individual 29 characteristics consisting of the number of children in a family; the age of the youngest child in the family; the youngest child being below three years old; the youngest child being below 10 years old; whether there are any boys in the family; the residential parent’s race, and the residential parent’s level of education.28

I run each specification in two ways: first with only year of custody fixed effects, and second with both year of custody fixed effects and state fixed effects. Including state fixed effects generally dilutes or eliminates the effect of the law. Given the size of the data set and the limited amount of variation across time, this is not surprising. This does not necessarily indicate that the laws do not affect custody arrangements, but rather that the data do not provide a good way of knowing whether it is the laws or the characteristics of a state that affect custody arrangements.29 Joint custody laws may affect joint custody practices more for some types of people than others. In particular, families with the resources to provide two separate homes for children and families with the ability to hire lawyers or mediators may have been more likely to take advantage of these laws. I therefore run the regressions for subsets of parents: those with at least a high school degree, those with at least a college degree, and whites and non-whites.

Table 4 presents the results of these regressions. The top panel shows the result for the prevalence of joint legal custody, the middle panel for joint physical custody, and the bottom panel examines whether parents who have a child support order in place receive all the child support owed. Joint custody laws that have not been in place for very long have no effect on

28 In these regressions, I do not control for family income or parents’ poverty levels because these variables are likely to be endogenous (e.g. one hypothesis is that single-mother families have lower income because joint custody arrangements decrease the amount of child support they are granted). However, as a test for robustness, I run specifications that include these variables and find that my results are robust. 29 Of course, given that joint custody was very rare up until the late 1970s, states with higher levels of observed joint custody are states where joint custody increased. Perhaps joint custody would have increased over time without the enactment of the laws, but given the discretion of judge, it seems likely that the laws allowed for this increase to occur. 30 custody, but joint custody laws that were passed 6 or more years before the year of custody determination have a strong positive effect on legal custody, though this effect is largely erased with the addition of state fixed effects. This effect is particularly strong for those with more education. For college educated parents, for example, joint custody laws (eventually) increase legal custody by about 10 percentage points, even with the inclusion of state fixed effects. By contrast, the results of the custody laws on physical custody suggest that there is no effect at all.

In some specifications, the results are even negative, although small. This is puzzling given that the Vital Statistics data did find an effect the joint custody laws on joint custody arrangements, and that dataset studied exclusively joint physical custody arrangements. One explanation for this difference in findings is that the Vital Statistics data studies only families of divorce, whereas the CPS data studies all households with children who have at least one parent who lives outside the home. Perhaps joint custody laws were not enough to convince judges to grant never- married fathers joint custody, so the inclusion of the children of non-married parents dilutes the effect of the laws such that they no longer predict joint physical custody arrangements.

Finally, the bottom panel shows that joint custody laws have a very important effect on receipt of child support. Joint custody appear to increase the probability of child support being paid, particularly for those with less education. It makes sense that this effect is stronger for parents with less education because most of the parents who have a college degree receive all of their child support payments, regardless of the law, so the effect of this law of increasing already-high rates of payment is small. (Most of the parents who have a college degree receive all their child support payments.) This result is very much in keeping with the bonding and monitoring theory discussed in Part III. Parents with joint legal custody have a greater ability to 31 monitor how their support is being used and to maintain a close relationship with their children, and so are more likely to stay current with their child support payments.

32

Table 4 Do Custody Laws Affect Custody Arrangements: Evidence from the CPS Parents Have At Least a High School At Least a College All Degree Degree Dependent Variable: Has a Joint Legal Custody Agreement (1) (2) (3) (4) (5) (6) 1-5 Years of -0.01 -0.01 -0.01 -0.01 0.03 0.03 Joint Custody Law (.02) (.02) (.02) (.02) (.04) (.05) 6 + Years of 0.04** 0.01 0.05** 0.02 0.14*** 0.10** Joint Custody Law (.02) (.02) (.02) (.02) (.04) (.05) R squared 0.08 0.1 0.08 0.1 0.07 0.1

Dependent Variable: Has a Joint Physical Custody Agreement 1-5 Years of 0 -0.02 -0.01 -0.02* 0 -0.01 Joint Custody Law (.01) (.01) (.01) (.01) (.03) (.04) 6 + Years of 0.01 -0.03** 0.01 -0.03** 0.03 -0.02 Joint Custody Law (.01) (.01) (.01) (.01) (.04) (.04) R squared 0.04 0.05 0.04 0.05 0.05 0.08

Dependent Variable: All Child Support Received if Owed 1-5 Years of 0 0.02 0 0.01 -0.11** -0.06 Joint Custody Law (.02) (.03) (.03) (.04) (.05) (.06) 6 + Years of 0.06*** 0.09** 0.07*** 0.10** -0.03 0.04 Joint Custody Law (.02) (.03) (.02) (.04) (.03) (.06) R squared 0.03 0.04 0.03 0.04 0.05 0.08 Year of Custody Fixed Effects X X X X X X State of Custody Fixed Effects X X X Sources and notes: These data are from IPUMS-CPS. N = 20,259. In each regression, I include a full set of control variables. These include the number of kids in house; the age of youngest child in house; whether there are any kids under 3 in the house; whether there are any kids under 10 in house; whether there are any male children under 18 in the house; whether the child is female; the age of the child; the race of the residential parent and the residential parent's education level. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

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Part V. The Dynamics of Joint Custody Arrangements

Understanding how joint custody actually affects children’s experience of divorce is an important element in understanding how custody affects children’s future outcomes. The CPS data provide rich detail about the interactions between children of divorce and their parents.

Figure 3B shows the fraction of children of divorce who had any contact with a non-resident parent based on the year of divorce. In 1980, fewer than 60% of children were in contact with their non-resident parent; by 2010, this number had increased to 85%. Figure 3A demonstrates that the likelihood of having a legal child support agreement has actually slightly decreased over time, which may initially seem surprising, particularly because other forms of legal agreements over children—both joint physical custody agreements and joint legal custody agreements—are growing over time, as depicted in Figure 2A. When looking at these two trends together—the increase in joint custody agreements and the decrease in legal child support agreements—one possible explanation appears: the rise in joint custody agreements has caused the fall in legal child support agreements. This is likely because if the expectation is increasingly that estranged parents will share the responsibilities of taking care of the child, then a family court judge may be less likely to rule that the “breadwinner” of the pair must pay child support.30

30 In states’ laws, there is a close relationship between child support and child custody. In Virginia, for example, child support is reduced when parents have joint physical custody, defined as having 90 overnights per year. Parents appear to take advantage of the inverse relationship between time with children and child support payments, as in Virginia a large proportion of parents report that they spend exactly 90 overnights with their children (Emery 2009). 34

Figure 3A: Legal Child Support Figure 3B: Any Contact with Agreement Other Parent 80% 90% 75% 85% 70% 80% 65% 75% 60% 70% 55% 65% 50% 60% 1979 1983 1987 1991 1995 1999 2003 2007 1979 1983 1987 1991 1995 1999 2003 2007 Year of Custody Agreement Year of Custody Agreement

Figure 3C: Number of Days Figure 3D: Received All Spent with Other Parent Ordered Child Support 120 Payments 100 85% 80 75% 60 40 65% 20 55% 0 45% 1979 1983 1987 1991 1995 1999 2003 2007 1979 1983 1987 1991 1995 1999 2003 2007 Year of Custody Agreement Year of Custody Agreement

Figure 3 Joint Custody Dynamics Sources and Notes: All data from IPUMS-CPS (1994-2010).

35

I use the CPS data to examine the association between joint custody and other dimensions of family dynamics. For family i with a custody agreement at time t living in state s in the CPS data, I run regressions of the form:

(2) 푂푈푇퐶푂푀퐸푖푡푠 = ∝ + 훽1푂푛푙푦퐿푒푔푎푙푖 + 훽2푂푛푙푦푃ℎ푦푠𝑖푐푎푙푖 + 훽3퐿푒푔푎푙푎푛푑푝ℎ푦푠𝑖푐푎푙푖 + 훽4푁표푓푎푢푙푡푙푎푤푡푠 + τ푡 + δ푠 + 푡 ∗ 훿푠 + 푋푖 + 휖푖푡푠

I examine the relationship between joint agreements and four different outcomes: whether a family has a legal child support agreement (rather than no agreement or an informal agreement)31; whether, if one parent was owed child support within the last year, the parent received all that was owed; the number of days a child spent with her non-residential parent32 within the last year; and whether or not the child had contact with her non-residential parent within the last year. I code three variables for joint custody agreements. Onlylegal is equal to one when the family has only a joint legal custody agreement, Onlyphysical is equal to one when the family has only a joint physical custody agreement, and Legalandphysical is equal to one when the family has both a joint legal and a joint physical custody agreement.33 Nofaultlaw is a binary variable that equals one when a no-fault divorce law is in place in a family’s state of divorce at the time of custody agreement. Because these regressions test the direct effect of having one of

31 Child support agreements differ from child custody agreements, though the two are related. Child support agreements determine the ongoing, periodic payments made by one parent--typically the noncustodial parent--to the other to help pay for the child’s food, education, clothing, housing, etc. Child support is partly based on the parents’ gross income (The People’s Library). 32 I use the term “residential parent” to refer to the parent that answers the survey. This parent responded “yes” to the question of whether or not a child lives with him/her that has a parent outside of the home. I refer to the other, non- surveyed parent as the “non-residential parent.” If the two parents do not share a custody agreement, then the non- residential parent is also a non-custodial parent. If the two parents two share custody then both residential and non- residential parents are considered custodial parents of the child. It is likely that some parents report children as living there who do not technically live there (if, for example, the child is there only on weekends), though it is not clear what direction this measurement error would bias the results. 33 Thus the omitted category is those families with no joint custody agreement (so one parent has both sole legal custody and sole physical custody of the children). 36 these custody arrangements rather than the indirect and thus weaker effect of having a law in one’s state, I am able to include a full set of year and state fixed effects and state-specific time trends in each regression, measured by τ푡, δ푠 and t ∗ δ푠. Finally, 푋푖 is a vector of individual characteristics, which are the same as those included in the regressions run using equation (1).

The results of these regressions are reported in Table 5. As explained earlier, the summary statistics for this dataset show that only 2% of families have only joint physical agreements, so the main coefficients of interest are the coefficient on having only legal joint custody (훽1) and the coefficient on having both legal and physical joint custody (훽3).

Column (1) shows that having only a legal joint custody agreement is associated with an

18 percentage point increase in the likelihood of having a legal child support agreement, whereas there is no significant effect of having both a legal and a physical joint on the likelihood that a family will have a legal child support agreement. The difference in these effects likely results from judges, lawyers or parents deciding that a child support agreement is not necessary if the parents—at least in theory—are both taking physical responsibility for the child. This could put additional economic stress on one parent if the parents share physical custody and therefore neither parent receives child support payments but the lion’s share of the economic responsibility of the child is still on one parent.

However, Column (2) demonstrates that both types of joint custody—having only a legal joint agreement and having both a legal and a physical joint agreement--raise the likelihood that, if child support is owed, it will actually be paid in full, though this effect is stronger when couples share both forms of custody. This increase in parents actually paying the child support owed is an incredibly important aspect of custody battles, as approximately $14 billion in child support is left unpaid every year, or approximately 1 in every 3 dollars owed (Reyes 2013). In 37 the CPS data, on average only 67% of child support owed if paid in full. This supports the bonding and monitoring theories I discuss in Part III, as it shows that if, obligated to pay child support, parents are more willing to actually pay if they have security that they will continue to spend time with and be able to monitor their kids.

Column (3) demonstrates that having only a legal joint agreement is associated with an increase in the number of days a child spends with his non-residential parent, by approximately

7.5 days per year. If a family has both a legal and a joint physical agreement, this effect is quadrupled. The direction and significance of these last results are not surprising, but the magnitude of the results may seem small, particularly for the effects of having a physical joint custody agreement. It suggests that, in most cases, the children with joint custody agreements are not those who, in the absence of a joint agreement, would never have seen their non-resident parent. Typically, these children would have otherwise had sole custody agreements with visitation rights for the non-resident parent. The differences between visitation and joint custody in terms of actual time spent with each parent is not well defined. For instance, a situation in which a child sees one parent only 30% of the time could results from either a joint custody arrangement or a sole custody arrangement with visitation rights.34 As a result, the result of a joint agreement in terms of time spent with the other parent may not be large.

Fourth and finally, column (4) shows that having either only a joint custody agreement or both forms of joint agreements increase the likelihood of being in contact with one’s non- residential parent sometime within the last year by 21 percentage points. It is interesting that this effect is no larger when a family has both joint and legal joint custody rather than just legal joint

34Common visitation arrangements include every other weekend and one night per week; this is about 8 days out of every 28, or just under 30 percent. Thus, 30 percent or more is more than the typical visitation. 38 custody. Perhaps having any sort of joint custody agreement goes a long way in ensuring that children have at least some contact with their non-residential parent.

Of course, because these results are using actual custody arrangements, they likely reflect some selection effects. A family with a joint custody arrangement has either chosen to have a custody arrangement or has been deemed equipped enough to handle a joint custody arrangement by a judge. Thus families with joint custody arrangements will almost certainly differ than families with other types of custody arrangements. For example, the CPS data show that having a white parent increases the chance of having either a legal or a physical joint custody arrangement by over 15%. Although I attempt to address these issues by controlling for the race and education level of the residential parent, t the potential for selection effect exists.

Nonetheless, the correlations among these variables are interesting and instructive. For example, the fact that joint custody is not associated with a significant increase in time spent with children suggests that those who choose or are awarded joint custody would otherwise spend significant amounts of time with their children. To the extent the positive aspects of joint physical custody is that it increases time spent with both parents, these data suggest that these effects might not be that large.

39

Table 5 How Custody Arrangements Affect Children's Environments Parent Has Legal Received All No. Days Child Support Child Support Spent with Contact with Agreement Owed Other Parent Other Parent

Has Only Legal Joint Custody Agreement 0.18*** 0.07*** 7.49*** 0.21*** (0.02) (0.01) (2.29) (0.01) Has Only Physical Joint Custody Agreement 0.08*** 0.07* 2.42 0.17*** (0.02) (0.04) (5.04) (0.02)

Has Both Legal and Physical Joint Custody Agreement -0.01 0.10*** 29.12*** 0.21*** (0.02) (0.01) (2.74) (0.01)

R-squared 0.07 0.06 0.06 0.10

Sources and notes: These data are from IPUMS-CPS. N= 20,259. In each regression, I include year of divorce fixed effects, state of divorce fixed effects, state of divorce time trends, and a full set of control variables, including the race and education of the parents. In each regression, I also include a set of variables controlling for the number of children in the house; the age of youngest child in house; whether there are any kids under 3 in the house; whether there are any kids under 10 in house; whether there are any male children under 18 in the house; whether the child is female; the age of the child; the race of the residential parent and the residential parent's education level. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

40

Part VI. The Long-Term Effects of Joint Custody Laws on Children

Part VI.A. Census Data

The previous sections have demonstrated that joint custody laws do increase joint custody arrangements. Part V provides some evidence that, when a family has a joint custody arrangement, family dynamics are better, though the arrangement might make some families more financially vulnerable. In this section, however, I turn to the effects of joint custody in the long-term. To do so, I use the 1990, 2000, and 2010 Decennial Census of Population and

Housing, which I accessed through the Integrated Public Use Microdata Series website (IPUMS).

I assume that state of birth (which the Census reports) is the same as state of childhood, and use each person’s age and birth state to determine the divorce and custody laws prevailing during their childhood. This allows me to examine the long-term implications of growing up in a no- fault divorce or joint custody regime. Unfortunately, the data do not include any other information on childhood. I do not know whether a respondent’s parents were divorced, and, if they were, the type of custody arrangement the child experienced.

I restrict my sample to 25-50 year olds. I choose to exclude respondents under 25 years old because younger adults may still be in school, and thus their work experience and earnings may not be a good measure of their earnings capability. I exclude respondents older than 50 years old because very few respondents this age will have been exposed to either of the laws as a youth. I present the means of the data in Table 6.

41

Table 6 Census Summary Statistics N Mean SD

Avg Legal Joint Custody in State During Youth 2,400,000 0.05 0.08 Avg Physical Joint Custody in State During Youth 2,400,000 0.03 0.05

Exposed to Joint Laws as Youth 2,400,000 0.38 0.49 Exposed to No-Fault Law as Youth 2,400,000 0.54 0.50 Exposed to Both Laws as Youth 2,400,000 0.30 0.46

Proportion of Youth with Joint Laws 2,400,000 0.18 0.30 Proportion of Youth with No-Fault Laws 2,400,000 0.33 0.39 Proportion of Youth with Both Laws 2,400,000 0.14 0.28

White 2,400,000 0.84 0.37 Black 2,400,000 0.11 0.31 Female 2,400,000 0.51 0.50

No. Years Education 2,400,000 13.64 3.18 High School Degree 2,400,000 0.89 0.31 College Degree 2,400,000 0.27 0.45

Below Poverty Line 2,400,000 0.09 0.29 Wage and Salary Income 2,400,000 $34,667 $44,243

Sources and notes: These data are from IPUMS-USA and IPUMS-CPS.

Part VI.B. Variation in Exposure to Divorce and Custody Laws

My analysis focuses on the effects on adult outcomes of exposure to different divorce laws and different child custody laws before age 18. Because I restrict my data to 25 to 50 year olds in 1990 and later, the earliest relevant year in my sample is 1940 (when a 50 year old in

1990 born) and the latest relevant year is 2003 (when a 25 year old in 2010 was born).

To examine the effects of laws on adult outcomes, I examine the share of childhood years

(0-18) during which a person was exposed to joint custody regimes. This measure is related to 42 the probability that, if a child’s parents divorced, they divorced under a joint custody regime. For example, Massachusetts adopted joint custody laws in 1983. If a respondent in the 2000 Census is 30 years old, then he was born in 1970 and he turned 18 in 1988. This means that that he was exposed to joint custody laws for 5 out of 18 years of his childhood, or 28%. A 40-year-old respondent in the 2000 Census, however, would be born in 1960 and would turn 18 in 1978.

Thus this respondent would no youth exposure (0%) to joint custody laws.

I have three basic measures of joint custody exposure. All three measures assume that a person’s state of birth (which is reported in the Census) is also the state in which they grew up.35

My first measure examines the exposure to joint custody laws. I define the variable Jointlaw as the fraction of childhood years during which a respondent’s state of birth had joint custody laws; a value of 1 for this variable means that joint custody laws were introduced in a respondent’s state in their year of birth or before, so that they were exposed to joint custody laws throughout childhood. I also use this method to define Nofault, the share of childhood years during which a respondent’s state of birth allowed no-fault divorce.

The other measures of joint custody assess exposure to joint custody practices. I define

JointLegalPractice and JointPhysicalPractice as the average rates of actual joint legal and physical custody arrangements, respectively, in a person’s state of birth when she is between 0 and 18. This measure enables me to test whether joint custody practices—as opposed to joint custody laws—affect outcomes. As discussed above, although joint custody laws do predict joint custody practices, the laws are not perfectly predictive, so investigating the effects of actual joint custody practices provides another test of the welfare consequences of joint custody.

35 Unless no one in the sample had ever migrated across states before turning 18, then this measure will not be able to capture the true treatment status for everyone in the sample. Gruber (2000) also assumes that one’s state of birth is one’s state of residence as a youth when exploring the effects of youth exposure to unilateral divorce laws. See Part VII.A for a discussion of this issue and my method of addressing the problem. 43

To calculate these alternative measures, I use data from the CPS Child Support

Supplements discussed above to calculate the average legal and physical joint custody rates in a person’s state of birth from birth through age 18. For example, for someone born in 1980, I calculate the average rates of physical and joint legal custody in her state from 1980 to 1997 and use these as a measure of the average prevalence of joint custody practices in her childhood. One issue with this strategy is that the CPS has very little information on custody determinations prior to 1980. But, as noted above, the practice of joint custody was extremely uncommon prior to

1980, so I assume that joint custody rates were zero in all states prior to 1980. Because of the relatively small sample sizes in the CPS, there are a number of missing observations even after

1980. More specifically, for some of the smaller states such as Maine and Vermont, I have rates of joint custody arrangements for only a subset of the years I have for larger states (for the majority of states, I have rates for most years between 1980 and 2010). To address this issue, I simply calculate the average joint custody rate over the years for which I have data. 36

Part VI.C. Identification Strategy

My main research question is: Do children who had more exposure to joint custody laws and practices have different outcomes as adults? Several papers have tried to answer similar questions, both for the effect of custody laws and for the effect of divorce laws. However, most of these studies share one central limitation: divorce or the granting of a joint custody agreement is not an exogenous event with respect to other determinants of child outcomes. In the case of custody arrangements, certain types of families elect to elect to obtain a custody agreement, and judges are more likely to award joint custody when both parents seem fit and have good

36 For example, for someone born in 1980, if I am missing observations for 1982, I would sum the rates of joint custody for the non-missing years between 1980 and 1998, and divide by 17. 44 relationships with the children. Thus, simply evaluating the outcomes of children based on whether they were subject to sole or joint custody would be fraught with selection effects. A number of studies have attempted to address this issue by controlling for socioeconomic characteristics in assessing the impact of divorce or joint custody agreements (e.g. McLanahan and Sandefur 1994). However, even conditional on background characteristics such as socioeconomic status, there may be unobservable differences between the families that choose to divorce and those who do not, as well as unobservable differences between the families that obtain joint custody agreements and those that do not, and these differences can affect children’s outcomes. For example, in the case of joint custody agreements, it may be the families in which fathers are most dedicated to their children that obtain joint custody agreements, and this could lead to better outcomes for children not because of joint custody per se, but rather because of the positive effects of having a devoted father.

To remedy these selection problems, I examine the effect of joint custody on the future outcomes of children by analyzing plausibly exogenous variation in joint custody by state and by year. By using only cross-state and cross-time variation, I eliminate the sample selection problems that arise when examining only children of divorce or only children who grew up with joint custody. This strategy is similar to that employed by Gruber (2000) in studying the long- term effects of changes in divorce law on children.

My basic approach is to analyze how adult outcomes are affected by the state joint custody laws prevailing during childhood. The calculation of childhood exposure to joint custody laws depends on only two factors: the year of birth and the state in which someone grew up, because these will determine what laws prevail during their childhood. Thus, the basic strategy is 45 to calculate for each person the exposure to joint custody during childhood, and see how this affects their adult outcomes.

However, in order to isolate the effects of joint custody, I need to control for other factors that might be correlated with year of birth and state that might also affect outcomes. First, to control for the possibility that states with better or worse outcomes—higher or lower levels of education, for example—systematically introduced laws earlier than other states, I include state fixed effects in the regression. Thus, it is only differences across people within a state that is used to identify the effects of laws. Second, it is important to control for changes in education and other outcomes that have occurred over time—since joint custody increased over time, I do not want to confound the effects of general trends in achievement with those of joint custody. To control for these trends, I include fixed effects for each individual’s year of birth and for each

Census year. If later cohorts had better or worse outcomes on average, these fixed effects will pick that up. Thus, my strategy is similar to a difference-in-difference approach: I am examining whether the difference in outcomes across cohorts in one state compared to the difference in outcomes across cohorts in another states are related to joint custody exposure.

For example, consider educational outcomes in Montana and Rhode Island for cohorts born in 1960 and 1970. Montana adopted joint custody laws in 1981, and Rhode Island adopted joint custody laws in 1992. Thus the 1960 cohort had no joint custody exposure in either state; the 1970 cohort was exposed to joint custody in Montana but not in Rhode Island. By including both state and year of birth fixed effects, the variation used to test the effects of joint custody exposure is as follows: are the outcomes of the 1970 cohort relative to the 1960 cohort in

Montana different from the outcomes of the 1970 cohort relative to the 1960 cohort in Rhode 46

Island? More generally, I ask whether relative changes in outcomes across cohorts are related to the extent of exposure to joint custody laws.

One final concern is that states that enacted joint custody laws earlier were states where other factors were changing. For example, perhaps joint custody laws were enacted in states where equality between the genders was increasing. Then, the introduction of joint custody might appear to be lead to difference in outcomes, but perhaps the real cause would be the increasing gender neutrality of the state. To control for this possibility, I also include a separate time trend for each state. This time trend should account for any changes in outcomes that are the result of changes in a state that are occurring gradually over time. In addition, in all my regressions, I control for childhood exposure to no-fault divorce law, so as not to confound the effects of these laws on outcomes with those of joint custody.

My basic estimating equation is as follows: For individual i, born in year y in state b, and living at time t in state s, outcomes are:

(3) 푂푈푇퐶푂푀퐸푖푦푏푡푠 = ∝ + 훽1퐽표𝑖푛푡푚푒푎푠푢푟푒푦푏 + 훽2푁표푓푎푢푙푡푦푏 + β3τ푦 + β4τ푡 +

β5δ푏 + β6훿푠 + β7훿푏푡 + β8훿푠푡 + β9푋푖 + 휖푖푦푏푡푠 where OUTCOME is education (as measured by years of school, having a high school degree, having some years of college, having a college degree, and having an advanced degree37) and labor force outcome (poverty status, labor force participation, and log wages), Jointmeasure is a measure of exposure to joint custody in childhood, Nofault is childhood exposure to no-fault divorce, described above, Xi is a vector of individual characteristics (white, female), τy, τt, δb and

37 I use the Census variable “educd” to construct my educational attainment variables. I define “high school degree” as having at least a diploma, GED or some alternative credential. Thus with high school degrees as well as higher degrees are still counted in this group. I define “some college” as having any college experience, even if it is less than one year. I define “college degree” as having at least a bachelor’s degree. I define “advanced degree” as having a master’s degree, a professional degree beyond a bachelor’s degree, or having a doctoral degree. 47

δs are fixed effects for year of birth, year of Census, state of birth, and state of residence, respectively, and 훿푏푡 and 훿푠푡 are state of birth and state of residence time trends.

I use the three measures of exposure to joint custody described above: Jointlaw, which measures exposure joint custody laws, and JointLegalPractice and JointPhysicalPractice, which measure the prevalence of legal and physical joint custody, respectively, during childhood. The coefficient of interest is 훽1. If easier joint custody is good for children and young adults, then those who grew up in states with joint custody statutes should have better outcomes, and 훽1 will be positive.

Part VI.D. Results

Table 7 reports the effects of divorce and custody regimes on educational attainment, using the three different measures of joint custody. Most noteworthy, I find that, regardless of the measure used, joint custody lowers the likelihood that a person will obtain a high school degree.38 The coefficient on column (4) indicates that moving from a state without joint custody laws to one with joint custody laws during all 18 years of childhood decreases the likelihood of obtaining a high school degree by 2 percentage points. Using the coefficients on joint custody practices from column (5) and column (6), I calculate that increasing the prevalence of joint legal custody from 0% to 25% or joint physical custody from 0 to 15% (from 0 to roughly their pre- recession levels) decreases the likelihood of obtaining a high school degree by 1 percentage point. These are fairly large effects considering that many children never experienced divorce of their parents (although, as discussed in Part III, parental investment might change in the presence of joint custody laws, so not only children of divorce are affected.)

38 The results displayed in Table 7 and Table 8 are entirely robust to the inclusion of age time trends and year of birth time trends. 48

Besides this effect on high school, there is some evidence that physical joint custody practices lead to overall fewer years of education, shown in column (3). In addition, there is some weaker evidence that joint custody practices lead to fewer advanced degrees, shown in column (17) and column (18). However, this effect is not seen with joint custody laws, just practices. For all three outcomes for which we see significant effects of joint custody—years of education, high school degree, and advanced degree—the most significant effect is on physical joint custody practices. This is perhaps unsurprising, as these arrangements add the most instability to kids’ lives by forcing them to move around much more and, as hinted at in the previous section, it is these arrangements that often diminish child support payments (if parents are sharing joint physical custody, then one parent is less likely to have to pay the other parent to take care of the child).

In Table 8, I display the effects of joint custody on economic outcomes and find few significant effects. I test the effects of the three measures of joint custody on the likelihood that a person is living below the poverty line, the likelihood that she is in the labor force at the time of survey, and the log of her wages. Columns (5) and (6) demonstrate that being in a state with more joint custody arrangements—either legal or physical—decreases the likelihood that a person is in the labor force. Again we see that physical joint custody arrangements have the biggest effect. However, this is the only discernible effect on a person’s financial outcomes.

None of the three measures have a significant effect on the likelihood that a person is living below the poverty line or have an effect on a person’s wages. 49

Table 7: Educational Outcomes Years of Education High School Degree Some College College Degree Advanced Degree (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)

Joint Custody -0.07 -0.02** -0.00 0.01 -0.00 Laws (0.08) (0.01) (0.02) (0.01) (0.01)

Legal Joint -0.34 -0.04** -0.05 0.01 -0.04** Custody (0.23) (0.02) (0.05) (0.04) (0.01) Practices

Physical - Joint -0.76** -0.06** -0.10 -0.05 0.07*** Custody (0.37) (0.02) (0.08) (0.06) (0.02) Practices

R- squared 0.05 0.05 0.05 0.04 0.04 0.04 0.05 0.05 0.05 0.04 0.04 0.04 0.02 0.02 0.02 Sources and notes: These data are from IPUMS-USA and IPUMS-CPS. N = 2,400,000. All regressions include no-fault divorce laws, female, race, year of birth fixed effects, year of Census fixed effects, state of residence fixed effects, state of birth fixed effects, state of residence time trends and state of birth time trends. Standard errors are corrected for clustering at the state of birth level. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

50

Table 8: Financial Outcomes Below Poverty Line In Labor Force Log Wage (1) (2) (3) (4) (5) (6) (7) (8) (9) Joint Custody Laws -0.00 -0.00 0.02 (0.01) (0.01) (0.05) Legal Joint Custody Practices -0.04 -0.05*** 0.19 (0.02) (0.02) (0.17) Physical Joint Custody Practices -0.04 -0.09*** 0.25 (0.03) (0.02) (0.26) R- squared 0.04 0.04 0.04 0.04 0.04 0.04 0.03 0.03 0.03 Sources and notes: These data are from IPUMS-USA and IPUMS-CPS. N = 2,400,000. All regressions include no-fault divorce laws, female, race, year of birth fixed effects, year of Census fixed effects, state of residence fixed effects, state of birth fixed effects, state of residence time trends and state of birth time trends. Standard errors are corrected for clustering at the state of birth level. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

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Part VI.E. Exploring Effects by Gender

Since I found a significant result of the effects of joint custody, ideally I would like to dive deeper into the data and determine what characteristics of a person cause them to be negatively affected by joint custody laws or exposure to actual joint custody arrangements.

Unfortunately the Census data I use are not panel data, and thus I have no information on the characteristics of a respondent's family or the conditions of the respondent's childhood home.39

While I do have a lot of information on a person when he or she is between 25-50 years old, this information is endogenous, since I assume that a person has been affected by exposure to joint custody arrangements. Thus there are few exogenous characteristics on which I can split my sample.40 One of these few characteristics is gender. It is not unlikely that the effects differ by gender, first because joint custody typically means less responsibility to mom and more responsibility to dad, which can have different effects for male and female children. Second, there is a precedent for childhood conditions affecting children of different genders differently.

Maccoby et al. (1993) reported that girls who lived with their mother had somewhat higher grades and better psychological adjustment as compared to girls who lived with their father in a sole custody arrangement. Kelly (1994) concluded that girls who lived with their mother had

39 Rather than looking at adults, Leo (2008) studies the likelihood that eighteen-year old kids who still live at home will continue their education until at least grade 12. Because these kids still live at home, the Census links their data to their parents and Leo can separate those from divorced and intact families. Leo finds that those adversely affected by the laws are actually those from intact families, not from families of divorce. This is an interesting finding that needs further corroboration but that I cannot test. 40 Another characteristic is race. I run these regressions stratifying my sample by race and find large differences between white and black respondents, but because I have so little other information on these people I do not have enough information to make any conclusions about these differences. I find that, whether measured by laws or practices, joint custody significantly lowers educational attainment for blacks, but has a much more muted effect for whites. These results are included in Appendix Table 4. 52 significantly greater social competence, maturity, cooperativeness and self-esteem than did boys who lived with their mother.

Table 9 reports some of the results by gender. Joint custody lowers high school graduation rates about equally for boys and girls—although the effects for boys are somewhat larger, the differences are not statistically significant. Joint custody laws do have a significant and positive effect on women’s college graduation rates, but only when using laws and not practices. Thus these results show that men are slightly more strongly affected by joint custody, though the differences are not large.

53

Table 9 Are Effects on Education Different by Gender?

High School Degree Difference by Gender Men Women Significant?

Joint Custody Laws -0.020** -0.017** NO (0.009) (0.007)

Legal Joint Custody Practices -0.047** -0.038* NO (0.022) (0.020)

Physical Joint Custody Practices -0.058** -0.062** NO (0.027) (0.024)

College Degree

Joint Custody Laws -0.002 0.022** Yes (0.010) (0.010)

Legal Joint Custody Practices 0.004 0.025 NO (0.036) (0.043)

Physical Joint Custody Practices -0.058 -0.050 NO (0.056) (0.072) Sources and notes: These data are from IPUMS-USA and IPUMS-CPS. N = 1,178,448 for men and N = 1,221,552 for women. All regressions include no-fault divorce laws, female, race, year of birth fixed effects, year of Census fixed effects, state of residence fixed effects, state of birth fixed effects, state of residence time trends and state of birth time trends. Standard errors are corrected for clustering at the state of birth level. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

54

Part VII. Additional Robustness Checks

Although the identification strategy used in this paper is a reasonable one, it is not perfect. For one, it assumes that a person’s place of birth is the same as their place of childhood, which will not be true for everyone. And, more generally, it relies on the assumption that the exact timing of state joint custody laws and practices is independent of the timing of other forces that may also affect outcomes. However, as I showed above, the strategy is robust to including time trends by state, which means that the effects I am capturing are not simply picking up difference in state trends. In this section, I show that the results are also robust to a number of other estimating approaches.

Part VII.A. Robustness Check for Migration

As discussed in the empirical strategy section in Part VI.C, I assume that a person’s state of birth is also the state in which they grew up. Unless no one in the sample had ever migrated across states before turning 18, then this measure will not be able to capture the true treatment status for everyone in the sample. If children’s migration was random—if it was independent of states’ custody law changes and children’s long-term educational attainment—then, to the extent that there is measurement error, this measurement error will bias down my results toward zero.

Some members of the sample who had been exposed joint custody laws as youths would be classified as not experiencing them, and some members who had not been exposed would be classified as having been exposed. The bigger concern, however, is that migration might be correlated with in some way with the timing of the states’ custody laws and practices, which could again bias my results, though the source and direction of this bias is unclear.

Therefore, as a robustness check, I restrict the sample to individuals with the same state of birth and current state of residence, the “non-movers.” This check is not perfect, as it does not 55 account for those respondents who were born in a certain state, moved before they were 18, and then returned to their state of birth by the time of the survey, but this limits the magnitude of any potential bias. I find that my results are robust to this check.

Part VII.B. Robustness Check for Adult Exposure

In my main regression, I test the effect of youth exposure—defined as exposure between ages 0 and 18--to joint custody laws and practices on long-term outcomes. Implicit in this test, however, is the assumption that exposure to laws past one’s youth does not affect these outcomes. This is not necessarily the case. The environment one is in at age 20, for example, can affect a person’s decision in terms of whether or not to attend college, whether or not to go to school for a higher degree, or whether or not to enter the workforce.

Therefore, as an additional robustness check, I run my main regression but now control for adult exposure to joint custody laws and no-fault laws. I define adult exposure as the proportion of years of one’s adult life (life past age 18) in which she is exposed to certain laws, mimicking the way I define youth exposure. I find my results are largely robust to this check.

Column (11) in Appendix Table 3 shows my results for just looking at the likelihood of obtaining a high school degree, and I find that the coefficient of the effect of youth exposure to joint custody laws is not significantly different when this adult check is included.

Part VIII. Conclusion

In this paper, I attempt to shed light on the issue of joint custody. By exploiting the retrospective natures of the CPS Child Support Supplement, I calculate a previously unavailable series on the increase in joint custody over time. I find that both physical joint custody and legal joint custody have increased notably since the late 1970s. These increases have come largely at the expense of sole custody to the mother. Nonetheless, sole custody to the mother, either 56 informal or formal, is still the most common form of arrangement, accounting for roughly 75 of custody arrangements in 2009.

I exploit these CPS data as well as the Vital Statistics data to show that joint custody laws do lead to increases in joint custody arrangements, but that the effect appears to take a number of years to occur. These results suggest that the conditions under which the Coase theorem applies are likely not met in the case of joint custody. I then use the CPS data to investigate the dynamics of actual joint custody arrangements, both legal and physical. My results suggest that children in joint custody situations spend more time with both parents, but the effect is not large, as even in families without joint custody, children are often in contact with their non-residential parent.

Finally, this paper uses Census data and the timing of joint custody laws and practices to demonstrate that, on net, joint custody appears to have a negative effect on children. In particular, regardless of the measure used, increased joint custody appears to be associated with a decrease in high school completion rates. On the other hand, exposure to joint custody laws and practices has little to no significant effect on economic outcomes.

Although the downside of joint custody is limited to a reduction in high school completion, I find no discernable upside to the laws. In the sample, it does not appear as though anyone is being “helped” in the long-term by these laws. This suggests that laws currently being considered that would make joint custody the presumption in cases of divorce or would mandate a 50-50 split of time with the child in the case of divorce may be ill-advised.

It is worthwhile keeping in mind that my results find negative effects of joint custody over a period when joint custody was a relatively rare phenomenon. The scarcity of joint custody arrangements suggests that it was likely awarded only to parents who both seemed fit, able to cooperate and willing to share a custody arrangement. Children from these families are more 57 likely to benefit from joint custody than children in other families. Any laws that expand the prevalence of joint custody arrangements would likely lead to worse outcomes than I have uncovered, because they will impose joint custody on parents who are less equipped. This paper suggests that, at the very least, more research on the effects of joint custody is required before more aggressive joint custody policies are implemented.

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Appendix

Appendix Table 1: Custody and Divorce Regulations by State No- No- Joint Joint Fault Fault State Custody State Custody Divorce Divorce Laws Laws Laws Laws Alabama 1971 1997 Montana 1975 1981 Alaska 1935 1982 Nebraska 1972 1983 Arizona 1973 1991 Nevada 1973 1981 New Arkansas - 2003 1971 1974 Hampshire California 1970 1979 New Jersey - 1981 Colorado 1971 1983 New Mexico 1973 1982 Connecticut 1973 1981 New York - 1981 Delaware - 1981 North Carolina - 1979 District of - 1996 North Dakota 1971 1993 Columbia Florida 1971 1979 Ohio - 1981 Georgia 1973 1990 Oklahoma 1953 1990 Hawaii 1973 1980 Oregon 1973 1987 Idaho 1971 1982 Pennsylvania - 1981 Illinois - 1986 Rhode Island 1976 1992 Indiana 1973 1973 South Carolina - 1996 Iowa 1970 1977 South Dakota 1985 1989 Kansas 1969 1979 Tennessee - 1986 Kentucky 1972 1979 Texas 1974 1987 Louisiana - 1981 Utah - 1988 Maine 1973 1981 Vermont - 1992 Maryland - 1984 Virginia - 1987 Massachusetts 1975 1983 Washington 1973 - Michigan 1972 1981 West Virginia - - Minnesota 1974 1981 Wisconsin - 1979 Mississippi - 1983 Wyoming 1977 1993 Missouri - 1983

Sources and Notes: Coding of the no-fault laws comes from Mechoulan (2006). Coding of the joint custody laws comes from Halla (2009), who updates the legislative details in Brinig and Buckley (1998).

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Appendix Figure 1 Enactment of No-Fault Divorce Laws by State

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Appendix Table 2: Robustness Check for Vital Statistics Results Family Has Joint Physical Custody One or Both Both Parents Main Specification Probit Parents Residents Residents (1) (2) (3) (4) (5) (6) (7) (8)

1-5 Years of Joint 0.01 0.025* * 0.01 0.03*** 0.01 0.025*** 0.0080.025*** Custody Law at Time of Divorce -0.017 -0.008 -0.02 -0.01 -0.017 -0.008 -0.018 -0.009

6 + Years of Joint 0.13*** 0.045** 0.13*** 0.04** 0.130*** 0.044** 0.131*** 0.046** Custody Law at Time of Divorce -0.037 -0.017 -0.04 -0.02 -0.037 -0.017 -0.038 -0.018

Observations 238,706 238,706 238,706 238,706 237,914 237,914 204,626 204,626 R-squared 0.05 0.142 0.05 0.14 0.05 0.143 0.045 0.142 Year of Divorce FE X X X X X X X X State of Divorce FE X X X X Sources and Notes: These data are from the National Center for Health Statistics. The full set of control variables are those shown in Table 4. All regressions include wife and husband age fixed effects. Standard errors are corrected for clustering at the state of divorce level. I control for having no-fault divorce laws and for having both no-fault divorce laws and joint custody laws. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

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Appendix Table 3: Robustness Checks for Census Results High School Degree Controlling for Adult Main Specification Non-Movers Only Probit Exposure (1) (2) (3) (5) (6) (7) (8) (9) (10) (11) Joint Custody Laws -0.02** -0.02** -0.02** -0.03* (0.01) (0.01) (0.01)

Legal Joint Custody Practices -0.04** -0.05* -0.05** (0.02) (0.03) (0.02)

Physical Joint Custody Practices -0.06** -0.07** -0.07** (0.02) (0.03) (0.03)

Observations 2,400,000 2,400,000 2,400,000 1,526,696 1,526,696 1,526,696 2,400,000 2,400,000 2,400,000 1,526,696 R-squared 0.04 0.04 0.04 0.04 0.04 0.04 0.04

Sources and notes: These data are from IPUMS-USA and IPUMS-CPS. All regressions include no-fault divorce laws, female, race, year of birth fixed effects, year of Census fixed effects, state of residence fixed effects, state of birth fixed effects, state of residence time trends and state of birth time trends. Standard errors are corrected for clustering at the state of birth level. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level.

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Appendix Table 4 Education Outcomes by Race Years of Education High School Degree College Degree Advanced Degree Only Black Respondents Joint -0.29*** -0.04** -0.02** -0.01** Custody (0.09) (0.02) (0.01) (0.00) Laws Legal Joint -1.65*** -0.12** -0.16*** -0.09*** Custody (0.35) (0.05) (0.04) (0.02) Practices Physical Joint -2.01*** -0.19** -0.21*** -0.09** Custody (0.58) (0.07) (0.07) (0.04) Practices Only White Respondents Joint -0.04 -0.01* 0.01 -0.00 Custody (0.09) (0.01) (0.01) (0.01) Laws Legal Joint -0.33 -0.03* 0.00 -0.04** Custody (0.29) (0.02) (0.05) (0.02) Practices Physical Joint -0.82* -0.04** -0.08 -0.07** Custody (0.43) (0.02) (0.07) (0.03) Practices Sources and notes: These data are from IPUMS-USA and IPUMS-CPS. N = 267,692 in the top panel; N = 2,015,045 in the bottom panel. All regressions include no-fault divorce laws, female, race, year of birth fixed effects, year of Census fixed effects, age fixed effects, state of residence fixed effects, state of birth fixed effects, state of residence time trends and state of birth time trends. Standard errors are corrected for clustering at the state of birth level. ***Indicates significance at the 1% level. **Indicates significance at the 5% level. *Indicates significance at the 10% level. 65