Policy Credibility and the Design of Central Banks ROBERTO CHANG The author is a research officer in the macropolicy section of the Atlanta Fed’s research department. He thanks Jerry Dwyer, Adam Posen, Will Roberds, and Mary Rosenbaum for useful suggestions. N RECENT YEARS THE PRACTICE OF CENTRAL BANKING AROUND THE WORLD HAS BEEN PROFOUNDLY AFFECTED BY TWO TRENDS. THE FIRST IS TOWARD GRANTING CENTRAL BANKS GREATER INDEPEN- DENCE VIS-À-VIS OTHER BRANCHES OF THEIR GOVERNMENTS. THIS TREND IS CLEARLY EXPRESSED IN ITHE BRITISH GOVERNMENT’S MAY 1997 MOVE GRANTING THE BANK OF ENGLAND THE POWER TO SET SHORT-TERM INTEREST RATES. IT IS ALSO EVIDENT IN THE CURRENT EUROPEAN UNION’S PLAN FOR A SINGLE CURRENCY: THE 1992 TREATY OF MAASTRICHT PRESCRIBES THE CREATION OF A MONETARY AUTHORITY, THE EUROPEAN SYSTEM OF CENTRAL BANKS (ESCB), THAT WOULD BE FORMALLY INDEPEN- DENT OF ANY OTHER EUROPEAN GOVERNMENT OR INSTITUTION.1 IN ADDITION, MANY LATIN AMERICAN COUNTRIES, INCLUDING MEXICO, ARGENTINA, CHILE, AND PERU, HAVE ENHANCED THE INDEPENDENCE OF THEIR CENTRAL BANKS IN THE CONTEXT OF BROAD STRUCTURAL REFORMS. SOUTH AFRICA’S POSTAPARTHEID GOVERNMENT ALSO AGREED TO AN INDEPENDENT MONETARY AUTHORITY.2 The second trend influencing the nature of central These two trends have an underlying unity: they can banking is for countries to formally state that a central be seen as social responses to a more fundamental prob- bank’s sole objective should be to ensure price stability. lem of central bank credibility called the time inconsis- New Zealand, for example, in its Reserve Bank Act of tency of monetary policy. To aid in understanding this 1989, stated that the Bank’s monetary policy should be connection, this article discusses the nature of the time “directed to the economic objective of achieving and inconsistency problem and its economic implications. maintaining stability in the general level of prices.”3 The theory of time inconsistency stresses that mon- Likewise, Article 105 of the Maastricht Treaty establish- etary authorities are often tempted to promise low in- es that “the primary objective of the ESCB shall be to flation now and to try to surprise the public with maintain price stability.” The Bank of Canada and some unexpectedly higher inflation later. However, such other central banks are now bound to follow formal promises will not be believed because economic agents, inflation targets. In many other countries there is con- understanding the authorities’ incentives, realize that siderable debate about whether their monetary policy the promises will not be honored. Instead, economically should be exclusively geared toward attaining zero plausible outcomes have the property that monetary inflation.4 authorities are not able to systematically surprise the 4 Federal Reserve Bank of Atlanta ECONOMIC REVIEW First Quarter 1998 public. As this discussion will show, this property implies Although the empirical findings provide little sup- that the monetary authority cannot profit from reneging port that central bank independence helps lower inflation, on its announcements. In fact, it can only lose by doing it is too early to discard existing theory. According to the so: expected and realized inflation will often be higher theory, central bank independence is only one aspect than if the monetary authorities had made a binding of institutional solutions to inflation bias. It cannot by it- promise. This consequence is known as inflation bias. self eliminate inflation bias, so its emergence will not nec- This article explains how the creation of some essarily yield lower inflation. In addition, reputation-based institutions can be interpreted as social responses to approaches imply that inflation bias may be addressed time inconsistency. A society may try to ameliorate by noninstitutional means; hence, low inflation need not inflation bias by providing appropriate incentives for its require central bank in- monetary authorities to adhere to promises; institution- dependence. Both argu- al arrangements may be designed to reduce the gains to ments imply that there the authorities from creating unexpected inflation. One need not be a negative approach is to structure the compensation of central relation between central A trend influencing the bankers so as to punish them if inflation is outside some bank independence and target range, as in New Zealand. Alternatively, a society inflation even if current nature of central banking may try to constrain the policy instruments available to theory is valid. is for countries to formally the monetary authorities in order to make engineering state that a central bank’s inflation surprises more difficult. A country’s commit- An Economic Theory ment to fix its exchange rate can be understood in this of Credibility sole objective should be to way. For either approach to work, it is necessary that lthough the role ensure price stability. the monetary authorities be insulated from the rest of of credibility in the government. Hence central bank independence A monetary policy emerges as a necessary condition for institutional solu- has been recognized for tions to time inconsistency. a very long time, mod- Further theoretical analyses imply that such insti- ern research on credi- tutional mechanisms may not be necessary, however. In bility started only in the late 1970s with the publication particular, because monetary authorities are typically of seminal papers by Calvo (1978) and Kydland and engaged in a long-term relationship with the public, Prescott (1977). These two papers showed that the they can develop a reputation for honoring commit- then-novel hypothesis of rational expectations had pro- ments. The fear of losing a reputation for future “hon- found implications for the credibility of macroeconomic esty” is an important incentive that may deter a central policy in general and monetary policy in particular. bank from “cheating” today. Recent studies have shown Before focusing on these implications, it may be helpful that this incentive may be powerful enough to make to illustrate the basic nature of Calvo’s and Kydland and socially optimal outcomes attainable, even in the Prescott’s ideas with a simple example. absence of any institutional constraints. The example is about a fictional father, Federico, and Institutional approaches and reputational con- his adolescent son, Pablo, at the start of some week. Pablo cerns are both plausible solutions to the time inconsis- is at that age when he dislikes hard work and loves to be tency problem, and both have weaknesses according to extravagant. Federico wants to teach Pablo the value of existing theory. To aid in understanding their relative hard work, of course, and to that end he has convinced merits, this article discusses related empirical work. the neighbors to let Pablo mow their lawn for money. Empirical studies have largely focused on testing the Federico’s problem is that he cannot force Pablo to do the hypothesis that the central banks that are more inde- job. Instead, Pablo must be induced to mow the lawn, and pendent deliver lower inflation. Evidence favoring that the way to convince him is to allow him to get a tattoo in hypothesis has been analyzed in several studies focus- exchange for his effort. Federico would like to prevent ing on developed countries. However, it will be seen that Pablo from being tattooed, although this objective is not the relationship between central bank independence as important to him as inducing Pablo to mow the neigh- and inflation seems fragile, and it does not hold for less bors’ lawn. Federico would rather have Pablo mow the developed countries. neighbors’ lawn and use the corresponding payment to 1.See specifically Article 107 of the Maastricht Treaty. 2.See “Role Shifts for Central Bankers,” in the New York Times, November 15, 1994, sec. D. 3.Section 8, Reserve Bank of New Zealand Act of 1989, quoted in Walsh (1995b). 4.For debate about U.S. policy, see, for instance, “A Matter of Demeanor,” Wall Street Journal,May 20, 1994, sec. A, and “Time for an Economic Summit,” Wall Street Journal,September 28, 1994, sec. A. Federal Reserve Bank of AtlantaECONOMIC REVIEW First Quarter 1998 5 pay for, say, a good book. The prospect of reading a good affect the public’s decisions and to break its promises book is not enough to induce Pablo to do the lawn, though. once these decisions are made. If the public understands To make the example interesting, assume that the the policymaker’s incentives, it will disregard its promis- neighbors, mindful of Federico’s dilemma, will give the es. And this interaction will often result in a bad outcome money to Federico and not Pablo. Finally, let us push the for society. This is the essence of what Calvo and Kydland fictional nature of the example and assume that it is the and Prescott call the time-inconsistency problem. only interaction that Federico and Pablo will have. Although time inconsistency pervades all aspects of What is the likely outcome of this father-son example? government policy, its application to monetary policy has Federico cannot convince Pablo to mow the neighbors’ attracted the most research. A monetary authority, such lawn without promising as the Federal Reserve, typically has as a major objective him a tattoo. It seems to deliver low inflation. It may also have other objectives that it should be enough that can be accomplished by creating surprise inflation, for Federico to tell Pablo, that is, inflation rates over and above those previously A society may try to “If you mow the neigh- anticipated by the public. A case in point occurs if one constrain the policy bors’ lawn, you will be objective is to fight unemployment, as in the studies by allowed to use their pay- Kydland and Prescott (1977) and Barro and Gordon instruments available ment for whatever you (1983a).