OLIVIER JEAN BLANCHARD Massachusetts Institute of Technology LAWRENCE F. KATZ Harvard University Regional Evolutions IN 1987,the unemploymentrate in Massachusettsaveraged 3.2 percent, three percentagepoints below the nationalrate. Onlyfour years later, in 1991, it stood at 9.0 percent, more than two points above the national rate. For firmstaking investment decisions andfor unemployedworkers thinkingabout relocating, the obvious question is whether and when things will returnto normalin Massachusetts.This is the issue that we take up in our paper. However, instead of looking only at Massachusetts,we examine the generalfeatures of regionalbooms and slumps, studyingthe behaviorof U.S. states over the last 40 years. We attemptto answerfour questions. Whena typical U.S. state over the postwarperiod has been affected by an adverse shock to employment, how has it adjusted?Did wages de- cline relativeto the rest of the nation?Were otherjobs createdto replace those jobs destroyed by the shock? Or did workers move out of the state? Our interest in these questions extends beyond regionaleconomics. Blocs of countries, notably those in the EuropeanCommunity, are in- creasinglyeliminating barriers to the mobilityof goods and factors and moving toward adoptinga common currency. Once these institutional changes are in place, economic interactionsamong these countrieswill more closely resemblethose of U.S. states. This paper offers at least a We thank Rachel Friedberg, Jae Woo Lee, and especially Bill Miracky for research assistance. We thank Timothy Bartik, Hugh Courtney, Steve Davis, Jim Poterba, Xavier Sala-i-Martin, Bill Wheaton, and DRI for data. We thank Timothy Bartik, Rudiger Dorn- busch, Barry Eichengreen, Carol Heim, Ariel Pakes, Danny Quah, Sherwin Rosen, An- drei Shleifer, and participants in many seminars for comments and suggestions. We thank the National Science Foundation for financial support. I 2 Br-ookingsPapers on Economic Activity, 1:1992 glimpseof the natureand the strengthof the macroeconomicadjustment mechanismsupon which these countriesincreasingly will rely. We startby drawinga generalpicture of state evolutions over the last 40 years. The most strikingfeature is the range of employmentgrowth rates across states. Overthe last 40 years, some states have consistently grown at 2 percent above the nationalaverage, while some states have barely grown, with rates 2 percent below the nationalaverage. Rather thanleading to fluctuationsaround trends, employmentshocks typically have permanenteffects. A state that experiences an acceleration or a slowdown in growth can expect to returnto the same growth rate, but on a permanentlydifferent path of employment.The pictureis very dif- ferent when one looks at unemploymentrates. Relative unemployment rates have exhibited no trend; moreover, shocks to relative unemploy- ment rates have lasted for only one-halfdecade or so. Thus unemploy- ment patterns present an image of vacillating state fortunes as states move from above to below the nationalunemployment rate, and vice versa. Finally,the last 40 years have been characterizedby a steady con- vergenceof relativewages, a fact documentedrecently by RobertBarro and Xavier Sala-i-Martin(using personalincome per capita ratherthan wages).1As for unemployment,the effects of shocks to relative wages appearto be transitory,disappearing within a decade or so. We next develop a simplemodel that can account for these facts. We think of states as producingdifferent bundles of goods, all sold on the nationalmarket. We assume that productiontakes place underconstant returnsand that there is infinitelong-run mobility of both workers and firms. Under these two assumptions,our model impliesthat differences in the amenitiesoffered by states to either workers or firmslead to per- manent differences in growth rates. However, while employment growthrates differ, laborand productmobility lead to a stable structure of unemploymentand wage differentials.Thus the model can explainthe observed trends. Moreover, the model can help us think about the shocks and mechanisms underlying regional slumps and booms. As states produce different bundles of goods, they experience different shocks to labordemand and thus experience state-specificfluctuations. Shocks to labor demandfirst lead to movements in relative wages and unemployment.These in turn trigger adjustmentsthrough both labor 1. Barro and Sala-i-Martin (1991). Olivier Jean Blanchard and Lawrence F. Katz 3 and firmmobility, until unemploymentand wages have returnedto nor- mal. By then, however, employmentis permanentlyaffected; to what extent depends on the relative speed at which workersand firmsadjust to changes in wages and unemployment.In the rest of the paper, we use this model as a guide to interpretingthe joint movementsin relative em- ployment, unemployment,wages, and prices.2 Ourthird section clears some empiricalunderbrush. First, we exam- ine the issue of how much of the movementin state employmentis com- mon to states and how much is state-specific.The answeris simple. Ag- gregate fluctuationsaccount for most of the year-to-yearmovement in state employment, but their importancedeclines steadily over longer horizons. We then address the practicalissue of how one should define and constructstate relativevariables. After consideringalternatives, we define all variablesas logarithmicdeviations from the nationalaverage. We then look at joint movements in employment, unemployment, and participation.We find very similarresults across states. A negative shock to employmentleads initiallyto an increasein unemploymentand a smalldecline in participation.Over time, the effect on employmentin- creases, but the effect on unemploymentand participationdisappears after approximatelyfive to seven years. Put anotherway, a state typi- cally returnsto normalafter an adverse shock not because employment picks up, but because workersleave the state. These results raise an ob- vious set of questions: does employmentfail to pick up because wages have not declined enough or because lower wages are not enough to boost employment? We take up that questionin the next section, where we examinejoint fluctuationsin employment,unemployment, wages, and prices. We find that in response to an adverse shock in employment,nominal wages de- cline stronglybefore returningto normalafter approximately10 years. This decline triggerssome recovery in employment,but the response of job creation to wage declines is not sufficientto fully offset the initial shock. Using prices as well as wages, we characterizethe response of consumptionwages to employmentshocks. We find that consumption wages decline little in response to such shocks because housingprices, in particular,respond stronglyto employmentshocks. Thus migration 2. To our knowledge,such a descriptionis not availablein the regionalliterature. An importantexception is Bartik(1991), which covers some of the same groundas we do and providesa carefulliterature survey. We relateour conclusionsto Bartik'sbelow. 4 Brookings Paper-s on Economic Activity, 1:1992 in response to shocks appearsto result morefrom changes in unemploy- ment thanfrom changes in relativeconsumption wages. Throughoutour paper, we identify innovationsin employmentwith shocks to labor demand. Because we consistently find that positive shocks to employmentincrease wages and reduce unemployment,we are comfortablewith this identificationassumption. At the end of the pa- per, we follow an alternativeand more conventionalapproach. We ex- amine the effects of two observable and plausibly exogenous demand shocks: defense contracts, and predictedgrowth rates of employment, using the state industryshares and the nationalgrowth rates for each in- dustry. We characterizetheir effects on employment and unemploy- ment. The picture that emerges is consistent with our earlierfindings: the effects on unemployment of employment changes predicted by changes in defense spending and by our industry mix instrumentare quite similar to those we estimated for overall innovations in em- ployment. In the conclusion, we summarizethe mechanismsunderlying typical regional slumps and booms. Having done so, we returnto the case of Massachusetts. We then take up three larger issues. First, we ask whetherthe adjustmentprocess that we have characterizedis efficient. In response to shocks, should workers or jobs move? Our empirical work, which is largelydescriptive, cannot answer the question, but the results provide a few hints. We indicatehow sharperconclusions could result from furthermicro-empirical work on the natureof the labor mi- grationand on the ways in which shocks affect the process of job cre- ation and destruction.We then drawthe implicationsof our findingsfor an understandingof differencesin regionalgrowth, because we think- and our model formalizes-that the dynamic mechanismsat work are largely the same. Finally, we discuss the implicationsand limits of our analysis for Europeancountries as they move to form a common cur- rency area. Background We begin by laying out basic facts about regionalevolutions of em- ployment, unemployment,and wages in the postwarperiod. Olivier Jean Blanchard and Lawrence F. Katz 5 Figure 1. Persistence of Employment Growth Rates across U.S. States, 1950-90 Annual employment growth, 1970-90 (percent) 6 NV AK 4 NHWA TN2UM CO WY ID S AHI SM D VT DE MD MT 2 AI I] 0~~~~~~~~0RI M?I '~O',IN"'CT A OH WV IL / ~~NY 0 2 4 6 Annual employment growth, 1950-70 (percent) Source: Authors' calculations using data from Employment