but who will monitor the monitor suppose that providing incentives for a group of individuals in a strategic context requires a monitor to detect their deviations what about the monitor s deviations to address this question i propose a contract that makes the monitor responsible for monitoring and thereby provides incentives even when the monitor s observations are not only private but costly too i also characterize exactly when such a contract can provide monitors with the right incentives to perform in doing so i emphasize virtual enforcement and suggest its implications for the theory of repeated games jel c78 d23 d82 d86

communication in repeated games with private monitoring abstract the paper considers repeated games where each player can be observed by only a subset of the other players and where players can make public announcements about the behavior of the players they observed we address the following question what is the minimal level of observability that is required to obtain efficient outcomes the main result is that the limit set of sequential equilibrium payoffs when the discount factor tends to one contains the set of individual rational payoffs whenever each player is observed by at leasttwoother players journal of economic literatureclassification number c73

repeated partnership games with imperfect monitoring and no discounting in a partnership game each player s utility depends on the other players actions through a commonly observed consequence e g output profit price which is itself a function of the players actions and an exogenous stochastic environment if a partnership game is repeated infinitely and each player s payoff in the infinite game supergame is the long run average of his expected one period utilities then efficient combinations of one period actions can be sustained as nash equilibria of the supergame even if the players cannot observe other players actions or information but can only observe the resulting consequences

perfect public equilibrium when players are patient we provide a characterization of the limit set of perfect public equilibrium payoffs of repeated games with imperfect public monitoring as the discount factor goes to one our result covers general stage games including those that fail a full dimensionality condition that had been imposed in past work it also provides a characterization of the limit set when the strategies are restricted in a way that endogenously makes the full dimensionality condition fail as in the strongly symmetric equilibrium studied by abreu abreu d 1986 extremal equilibria of oligopolistic supergames j econ theory 39 191 228 and abreu et al abreu d pearce d stacchetti e 1986 optimal cartel equilibria with imperfect monitoring j econ theory 39 251 269 finally we use our characterization to give a sufficient condition for the exact achievability of first best outcomes equilibria of this type for which all continuation payoffs lie on the pareto frontier have a strong renegotiation proofness property regardless of the history players can never unanimously prefer another equilibrium

the power of forward guidance revisited in recent years central banks have increasingly turned to forward guidance as a central tool of monetary policy especially as interest rates around the world have hit the zero lower bound standard monetary models imply that far future forward guidance is extremely powerful promises about far future interest rates have huge effects on current economic outcomes and these effects grow with the horizon of the forward guidance we show that the power of forward guidance is highly sensitive to the assumption of complete markets if agents face uninsurable income risk and borrowing constraints a precautionary savings effect tempers their responses to changes in future interest rates as a consequence forward guidance has substantially less power to stimulate the economy in addition we show that the business cycle dynamics of our incomplete markets model differ substantially from its complete market counterpart this contrasts with the well known results of krusell and smith 1998 we present approximate representations that can easily be incorporated into standard business cycle models

monetary news shocks we pursue an empirical strategy to identify a monetary news shock in the u s economy we use a monetary policy residual along with other variables in a vector autoregression var and identify a monetary news shock as the linear combination of reduced form innovations that is orthogonal to the current residual and that maximizes the sum of contributions to its forecast error variance over a finite horizon real gdp declines in a persistent manner after a positive monetary news shock this contraction in economic activity is accompanied by a fall in inflation and a rapid increase in the nominal interest rate

inflation and output in new keynesian models with a transient interest rate peg a familiar result in the canonical dynamic new keynesian dnk model is that policymakers constrained by the zero bound can improve outcomes by promising to keep rates low after the zero bound is not binding we examine a general class of interest rate pegs in a variety of dnk models standard versions of the model produce counterintuitive reversals where the effect of the interest rate peg can switch from highly expansionary to highly contractionary for modest changes in the length of the interest rate peg this unusual behavior does not arise in sticky information models of the phillips curve

monetary fiscal policy interactions and fiscal stimulus abstract increases in government spending trigger substitution effects both inter and intra temporal and a wealth effect the ultimate impacts on the economy hinge on current and expected monetary and fiscal policy behavior studies that impose active monetary policy and passive fiscal policy typically find that government consumption crowds out private consumption higher future taxes create a strong negative wealth effect while the active monetary response increases the real interest rate this paper estimates markov switching policy rules for the united states and finds that monetary and fiscal policies fluctuate between active and passive behavior when the estimated joint policy process is imposed on a conventional new keynesian model government spending generates positive consumption multipliers in some policy regimes and in simulated data in which all policy regimes are realized the paper reports the model s predictions of the macroeconomic impacts of the american recovery and reinvestment act s implied path for government spending under alternative monetary fiscal policy combinations

the folk theorem with imperfect public information the authors study repeated games in which players observe a public outcome that imperfectly signals the actions played they provide conditions guaranteeing that any feasible individually rational payoff vector of the stage game can arise as a perfect equilibrium of the repeated game with sufficiently little discounting the central condition requires that there exist action profiles with the property that for any two players no two deviations one by either player give rise to the same probability distribution over public outcomes the results apply to principal agent partnership oligopoly and mechanism design models and to one shot games with transferable utilities copyright 1994 by the econometric society

the effects of monetary policy news and surprises there is substantial agreement in the monetary policy literature over the effects of exogenous monetary policy shocks the shocks that are investigated however almost exclusively represent unanticipated changes in policy which surprise the private sector and which are typically found to have a delayed and sluggish effect on output in this paper we estimate a new keynesian model that incorporates news about future policies to try to disentangle the anticipated and unanticipated components of policy shocks the paper shows that the conventional estimates confound two distinct effects on output an effect due to unanticipated or surprise shocks which is smaller and more short lived than the response usually obtained in the literature and a large delayed and persistent effect due to anticipated policy shocks or news news shocks play a larger role in influencing the business cycle than unanticipated policy shocks although the overall fraction of economic fluctuations that can be attributed to monetary policy remains limited

central bank communication and monetary policy a survey of theory and evidence over the last two decades communication has become an increasingly important aspect of monetary policy these real world developments have spawned a huge new scholarly literature on central bank communication mostly empirical and almost all of it written in this decade we survey this ever growing literature the evidence suggests that communication can be an important and powerful part of the central bank s toolkit since it has the ability to move financial markets to enhance the predictability of monetary policy decisions and potentially to help achieve central banks macroeconomic objectives however the large variation in communication strategies across central banks suggests that a consensus has yet to emerge on what constitutes an optimal communication strategy

estimating the effects of forward guidance in rational expectations models abstract simulations of forward guidance in rational expectations models should be assessed using the modest policy interventions framework introduced by eric leeper and tao zha that is the estimated effects of a policy intervention should be considered reliable only if that intervention is unlikely to trigger a revision in private sector beliefs about the way that monetary policy will be conducted i show how to constrain simulations of forward guidance to ensure that they are regarded as modest policy interventions and illustrate the technique using a medium scale dsge model estimated on us data i find that many experiments that generate the large responses of macroeconomic variables deemed implausible by many economists the so called forward guidance puzzle are not modest policy interventions those experiments should therefore be treated with caution since they may prompt agents to believe that there has been a change in the monetary policy regime that is not accounted for within the model more reliable results can be obtained by constraining the experiment to be a modest policy intervention in the cases i study the quantitative effects on macroeconomic variables are more plausible when this constraint is imposed

communication in repeated games with imperfect private monitoring this paper examines repeated games in which each player observes a private and imperfect signal on the actions played and in which players are allowed to communicate using public messages providing incentives for players to reveal their observations generates revelation constraints that combined with signal imperfections may be a source of inefficiencies however by delaying the revelation of their observations players may economize on the cost of deterring deviations and thereby avoid these inefficiencies because a player would not want to trigger a sanction that would penalize him too revelation constraints also tend to make sanctions difficult to enforce however with at least three players detecting deviations may not require that all the players reveal their observations in that case we obtain a nash threat version of the folk theorem with two players we do not obtain a similar result nevertheless we show that an efficient outcome can almost always be approximated

a robust folk theorem for the prisoner s dilemma we prove the folk theorem for the prisoner s dilemma using strategies that are robust to private monitoring from this follows a limit folk theorem when players are patient and monitoring is sufficiently accurate but private and possibly independent any feasible individually rational payoff can be obtained in sequential equilibrium the strategies used can be implemented by finite randomizing automata journal of economic literature classification numbers c72 c73 d82

perfect communication equilibria in repeated games with imperfect monitoring this paper introduces an equilibrium concept called perfect communication equilibrium for repeated games with imperfect private monitoring this concept is a refinement of myerson s myerson r b 1982 optimal coordination mechanisms in generalized principal agent problems j math econ 10 67 81 communication equilibrium a communication equilibrium is perfect if it induces a communication equilibrium of the continuation game after every history of messages of the mediator we provide a characterization of the set of corresponding equilibrium payoffs and derive a folk theorem for discounted repeated games with imperfect private monitoring

the effect of employment frictions on crime this article provides estimates on how long it takes for released inmates to find a job and when they find a job how less likely they are to be incarcerated an on the job search model with crime is used to model criminal behavior derive the estimation method and analyze policies including a job placement program the results show that the unemployed are incarcerated twice as fast as the employed and take on average 6 months to find a job the article demonstrates that reducing the average unemployment spell of previously incarcerated criminals by 3 months reduces crime and recidivism by more than 5

the power of communication abstract in this paper i offer two ways in which firms can collude secret monitoring and infrequent coordination such collusion is enforceable with intuitive communication protocols i make my case in the context of a repeated cournot oligopoly with flexible production prices that follow a brownian motion and no monetary side payments an environment where it has previously been argued that any collusion is impossible trade associations can easily facilitate collusion by mediating communication amongst firms jel d21 d43 l12 l13

econometric policy evaluation note for successive values of the endogenous variables y with the x treated as deterministic forcing variables here 0 is a parameter vector and the et are random shocks lucas correctly observed that such a formulation is inconsistent with a view of agents as optimizers except in special cases in which the future is irrelevant to present decisions it makes no sense to think of agents as optimizing if they know that their budget constraints are liable to shift arbitrarily i e in a way which is not characterized probabilistically as government policy changes lucas was led to augment the foregoing equation by adding to the system a government policy function

endogenous monitoring in a partnership game i consider a repeated game in which due to imperfect monitoring no collusion can be sustained i add a self interested monitor who commits to obtain private signals of firms actions and sends a public message the monitor makes an offer specifying the precision of the signals obtained and the amount to be paid in return first with a low monitoring cost collusive equilibria exist second collusive equilibria are monitor preferred third in monitor preferred equilibria firms payoffs are decreasing in the discount factor my model helps explain cartel agreements between self interested parties and firms in legal industries in the united states and europe

changes in the federal reserve communication strategy a structural investigation this paper structurally investigates the changes in the fed s communication strategy since the mid 1990s through the lens of anticipated and unanticipated disturbances to a taylor rule the anticipated disturbances are identified using treasury bond yield data in estimating a dynamic stochastic general equilibrium dsge model with a term structure of interest rates our estimation results show that the fed s decisions were unanticipated for market participants until 1999 but thereafter a larger portion of its future policy actions tended to be communicated in advance we also find that the relative contribution of the anticipated monetary policy disturbances to macroeconomic fluctuations became larger after 1999 the bond yield data is indispensable to these results since it contains crucial information on an expected future path of the federal funds rate

a structural decomposition of the us yield curve abstract by expanding the macro part of macro finance models historical fluctuations in us bond yields turn out to be largely consistent with the rational expectations hypothesis we estimate a medium scale macro finance dsge model of the term structure to establish this our finding contrasts with existing macro finance models and suggests that their small scale or non structural perspective on the macroeconomy mutes expectations thereby underestimating the expectations hypothesis potential out of sample forecasts are competitive with more flexible term structure models given the empirical validation we interpret various episodes through the lens of the model and investigate which structural shocks cause the yield curve to contain information about future growth

communication about future policy rates in theory and practice a survey we discuss the theoretical rationale for central bank communication about future policy rates either as part of inflation targeting or in the form of forward guidance we also summarize both actual central bank communication about future policy rates and empirical evidence on the effectiveness of these types of communication we argue that there is a disconnect between the theory and practice of forward guidance as theory assumes commitment on the part of the central bank while in practice central banks generally do not commit future theoretical research on forward guidance should therefore take the absence of commitment by central banks into account

the repeated prisoner s dilemma with imperfect private monitoring abstract in this paper i study a repeated prisoner s dilemma game in which monitoring is private and imperfect a partial folk theorem is proved for the case of almost perfect monitoring

communication in repeated games with costly monitoring abstract we study repeated games with discounting where perfect monitoring is possible but costly it is shown that if players can make public announcements then every payoff vector which is an interior point in the set of feasible and individually rational payoffs can be implemented in a sequential equilibrium of the repeated game when the discount factor is high enough thus efficiency can be approximated even when the cost of monitoring is high provided that the discount factor is high enough

efficiency and observability with long run and short run players we present a general algorithm for computing the limit as 1 of the set of payoffs of perfect public equilibria of repeated games with long run and short run players allowing for the possibility that the players actions are not observable by their opponents we illustrate the algorithm with two economic examples in a simple partnership we show how to compute the equilibrium payoffs when the folk theorem fails in an investment game we show that two competing capitalists subject to moral hazard may both become worse off if their firms are merged and they split the profits from the merger finally we show that with short run players each long run player s highest equilibrium payoff is generally greater when their realized actions are observed journal of economic literature classification numbers c72 c73 d21 d82 d92 e22