Knowledge that Transforms

This paper presents an approximate analytical solution to the optimal consumption and portfolio choice problem of an infinitely lived investor with Epstein-Zin-Weil utility who faces a constant riskless interest rate and a time-varying equity premium. When the model is calibrated to U. S. stock market data, it implies that intertemporal hedging motives greatly increase, and may even double, the average demand for stocks by investors whose risk-aversion coefficients exceed one. The optimal portfolio policy also involves timing the stock market. Failure to time or to hedge can cause large welfare losses relative to the optimal policy.

Recently, several central banks have lost their bank supervisory responsibilities, in part because it has not been shown that supervisory authority improves the conduct of monetary policy. This paper finds that confidential bank supervisory information could help the Board staff more accurately forecast important macroeconomic variables and is used by FOMC members to guide monetary policy. These findings suggest that the complementarity between supervisory responsibilities and monetary policy should be an important consideration when evaluating the structure of the central bank.

We present a model that links heterogeneity of preferences across ethnic groups in a city to the amount and type of public goods the city supplies. We test the implications of the model with three related data sets: U. S. cities, U. S. metropolitan areas, and U. S. urban counties. Results show that the shares of spending on productive public goods—education, roads, sewers and trash pickup—in U. S. cities (metro areas/urban counties) are inversely related to the city's (metro area's/county's) ethnic fragmentation, even after controlling for other socioeconomic and demographic determinants. We conclude that ethnic conflict is an important determinant of local public finances.

We examine the impact of increased abortion availability on the average living standards of children through a selection effect. Would the marginal child who was not born have grown up in different circumstances than the average child? We use variation in the timing of abortion legalization across states to answer this question. Cohorts born after legalized abortion experienced a significant reduction in a number of adverse outcomes. We find that the marginal child would have been 40–60 percent more likely to live in a single-parent family, to live in poverty, to receive welfare, and to die as an infant.

Do professional forecasters provide their true unbiased estimates, or do they behave strategically? In our model, forecasters have common information, confer actively, and thus know the true pdf of future outcomes. Intensive users of economic forecasts monitor forecasters' performance closely; occasional users are drawn to the forecaster who fared best in the previous period. In the resulting Nash equilibrium, even though economists have identical expectations, they make a range of projections that mimics the true probability distribution of the forecast variable. Those whose wages depend most on publicity produce forecasts that differ most from the consensus. Empirical evidence supports the model.

This paper develops a simple macroeconomic model that shows that combin-ing capital market imperfections together with unequal access to investment opportunities across individuals can generate endogenous and permanent fluctua-tions in aggregate GDP, investment, and interest rates. Reducing inequality of access may be a necessary condition for macroeconomic stabilization. Moreover, countercyclical fiscal policies have a role to play: in our model savings are underutilized in slumps because of the limited debt capacity of potential investors. Therefore, the government should issue public debt during recessions in order to absorb those idle savings and finance investment subsidies or tax cuts for investors. The most important single fact about saving and investment activities is that in our industrial society they are generally done by different people and for different reasons. (...) For years there might tend to be too little investment, leading to deflation, losses, excess capacity and unemployment. For other years, there might tend to be too much investment, leading to periods of chronic inflation—unless prudent and proper public policies in the fiscal and monetary fields are followed [Paul A. Samuelson, Economics 8th edition, 1970, pp. 196–198].

Psychological research indicates that people have a cognitive bias that leads them to misinterpret new information as supporting previously held hypotheses. We show in a simple model that such confirmatory bias induces overconfidence: given any probabilistic assessment by an agent that one of two hypotheses is true, the appropriate beliefs would deem it less likely to be true. Indeed, the hypothesis that the agent believes in may be more likely to be wrong than right. We also show that the agent may come to believe with near certainty in a false hypothesis despite receiving an infinite amount of information.

There is strong evidence that people exploit their bargaining power in competitive markets but not in bilateral bargaining situations. There is also strong evidence that people exploit free-riding opportunities in voluntary cooperation games. Yet, when they are given the opportunity to punish free riders, stable cooperation is maintained, although punishment is costly for those who punish. This paper asks whether there is a simple common principle that can explain this puzzling evidence. We show that if some people care about equity the puzzles can be resolved. It turns out that the economic environment determines whether the fair types or the selfish types dominate equilibrium behavior.