Knowledge that Transforms

With cheap talk, more can be achieved by long conversations than by a single message—even when one side is strictly better informed than the other. (“Cheap talk” means plain conversation—unmediated, nonbinding, and payoff-irrelevant.) This work characterizes the equilibrium payoffs for all two-person games in which one side is better informed than the other and cheap talk is permitted.

We propose an estimation method for models of conditional moment restrictions, which contain finite dimensional unknown parameters (theta) and infinite dimensional unknown functions (h). Our proposal is to approximate h with a sieve and to estimate theta and the sieve parameters jointly by applying the method of minimum distance. We show that: (i) the sieve estimator of h is consistent with a rate faster than n-super--1/4 under certain metric; (ii) the estimator of theta is root-n consistent and asymptotically normally distributed; (iii) the estimator for the asymptotic covariance of the theta estimator is consistent and easy to compute; and (iv) the optimally weighted minimum distance estimator of theta attains the semiparametric efficiency bound. We illustrate our results with two examples: a partially linear regression with an endogenous nonparametric part, and a partially additive IV regression with a link function. Copyright The Econometric Society 2003.

Public information in financial markets often arrives through the disclosures of interested parties who have a material interest in the reactions of the market to the new information. When the strategic interaction between the sender and the receiver is formalized as a disclosure game with verifiable reports, equilibrium prices can be given a simple characterization in terms of the concatenation of binomial pricing trees. There are a number of empirical implications. The theory predicts that the return variance following a poor disclosed outcome is higher than it would have been if the disclosed outcome were good. Also, when investors are risk averse, this leads to negative serial correlation of asset returns. Other points of contact with the empirical literature are discussed. Copyright The Econometric Society 2003.

A popular way to account for unobserved heterogeneity is to assume that the data are drawn from a finite mixture distribution. A barrier to using finite mixture models is that parameters that could previously be estimated in stages must now be estimated jointly: using mixture distributions destroys any additive separability of the log-likelihood function. We show, however, that an extension of the EM algorithm reintroduces additive separability, thus allowing one to estimate parameters sequentially during each maximization step. In establishing this result, we develop a broad class of estimators for mixture models. Returning to the likelihood problem, we show that, relative to full information maximum likelihood, our sequential estimator can generate large computational savings with little loss of efficiency.

Estimating Regulation-Induced Substitution: The Effect of the Clean Air Act on Water and Ground Pollution by Michael Greenstone. Published in volume 93, issue 2, pages 442-448 of American Economic Review, May 2003

How Welfare Policies Affect Child and Adolescent Achievement by Elizabeth Clark-Kauffman, Greg J. Duncan and Pamela Morris. Published in volume 93, issue 2, pages 299-303 of American Economic Review, May 2003

Payoffs from Panels in Low-Income Countries: Economic Development and Economic Mobility by Mark R. Rosenzweig. Published in volume 93, issue 2, pages 112-117 of American Economic Review, May 2003

This paper investigates the role of seasonal affective disorder (SAD) in the seasonal time-variation of stock market returns. SAD is an extensively documented medical condition whereby the shortness of the days in fall and winter leads to depression for many people. Experimental research in psychology and economics indicates that depression, in turn, causes heightened risk aversion. Building on these links between the length of day, depression, and risk aversion, we provide international evidence that stock market returns vary seasonally with the length of the day, a result we call the SAD effect. Using data from numerous stock exchanges and controlling for well-known market seasonals as well as other environmental factors, stock returns are shown to be significantly related to the amount of daylight through the fall and winter. Patterns at different latitudes and in both hemispheres provide compelling evidence of a link between seasonal depression and seasonal variation in stock returns: Higher latitude markets show more pronounced SAD effects and results in the Southern Hemisphere are six months out of phase, as are the seasons. Overall, the economic magnitude of the SAD effect is large.

Do Consumers React to Anticipated Income Changes? Evidence from the Alaska Permanent Fund by Chang-Tai Hsieh. Published in volume 93, issue 1, pages 397-405 of American Economic Review, March 2003