Coordination failure in repeated games with private monitoring

Players coordinate continuation play in repeated games with public monitoring. We investigate the robustness of such equilibrium behavior with respect to ex-ante small private-monitoring perturbations. We show that with full support of public signals, no perfect public equilibrium is robust if it induces a “regular” 2×2$2\times 2$ coordination game in the continuation play. This regularity condition is violated in all belief-free equilibria. Indeed, with an individual full rank condition, every interior belief-free equilibrium is robust. We also analyze block belief-free equilibria and point out that the notion of robustness is sensitive to whether we allow for uninterpretable signals.     

Global liquidity trap

How should monetary policy respond to a “global liquidity trap,” where the two countries may fall into a liquidity trap simultaneously? Using a two-country New Open Economy Macroeconomics model, we first characterize optimal monetary policy, and show that the optimal rate of inflation in one country is affected by whether or not the other country is in a liquidity trap. We next examine how well the optimal monetary policy is approximated by relatively simple monetary policy rules. The interest-rate rule targeting the producer price index performs well in this respect.     

Contagion of Self‐Interested Behavior: Evidence from Group Dictator Game Experiments

We examine how group decision‐making affects other‐regarding behavior in experimental dictator games. In particular, we assess whether the effects of iterated games differ for group and individual decision‐making and whether the difference in decision‐making style (individual or group) changes the perception of social identity. We make two findings on group decision‐making. First, group decisions become more selfish when repeating the game after changing group members. Second, a dictator group donates more to a recipient group at the same university than to a recipient group at a different university. These findings are not true for individual decision‐making.     

Self-Defeating Regional Concentration

Most policy debates on regional policies implicitly assume that there is too much concentration. In our two-region model of migration, desirable concentration fails to occur under some conditions, and undesirable concentration occurs in others. In the latter case, even though the individuals collectively prefer to be distributed evenly across the two regions, they end up concentrating into one region in their pursuit of a better life. Hence, the freedom to move can be self-defeating. We characterize the conditions for such self-defeating concentration to occur. The coordination failures between the entry decision of service firms and the migration decision of individuals are caused by the incompleteness of markets due to the endogeneity of the range of services available, which deprive the agents of the opportunity to signal demand and supply for potential services. The argument does not rely on price distortions, the nonconvexities implied by increasing returns and nontradedness, congestion externalities, nor myopia in migration decisions.     

Employer risk-adjustment transitions with inertial consumers: Evidence from CalPERS

Risk-adjustment policies, which transfer money from insurers with healthy consumers to those with sick consumers, are an important tool to contend with adverse selection in health insurance markets. While the steady-state properties of risk-adjustment have been studied extensively, there is less evidence on the transition phase of policy implementation. We study the introduction and removal of risk-adjustment at California Public Employees' Retirement System and show that these changes meaningfully impact premiums via plan differences in enrollee health status. Despite these premium differences, there is limited consumer resorting due to consumer inertia, though new active enrollees respond more fluidly. We show that, with inertial consumers, risk-adjustment changes have substantial distributional consequences, leading to worse outcomes for sicker consumers when removed and vice-versa when implemented. We estimate a model of plan choice with premium sensitivity, brand preferences, and inertia and use these estimates to study the interaction between risk-adjustment policies and the strength of inertia.