Shimer (2005) pointed out that although we have a satisfactory theory of why some workers are unemployed at any given time, we don't know why the number of unemployed workers varies so much over time. The basic Mortensen–Pissarides model does not generate nearly enough volatility in unemployment for plausible parameter values. This paper extends the Mortensen–Pissarides model to allow for informational rents. Productivity is subject to publicly observed aggregate shocks, and to idiosyncratic shocks that are seen only by the employer. It is shown that there is a unique equilibrium, provided that the idiosyncratic shocks are not too large. The main result is that small fluctuations in productivity that are privately observed by employers can give rise to a kind of wage stickiness in equilibrium, and the informational rents associated with this stickiness are sufficient to generate relatively large unemployment fluctuations.

This paper contains an equilibrium model of the labor market. The supply function allows f or temporal substitution in response to wage fluctuations, and the de mand function allows for adjustment costs. Two related issues are emp hasized: identification of supply and demand functions, and sources o f serial correlation in employment and real wages. When the supply an d demand shocks are AR(1) processes, the equilibrium process for empl oyment and real wages is a restricted VAR(2). The supply and demand f unctions are (locally) identified using only employment and real wage data. An illustrative application is presented, using U.S. data for 1948-71.

[The partial adjustment model has been used in many areas of applied economics as a description of optimal behavior in the face of adjustment costs. The model requires a specification of how expectations are formed; for example static or adaptive expectations are frequently specified. This paper analyzes the implications of a rational expectations specification. In applications, a series which measures expectations is usually not available, and various proxies have been suggested. If expectations are rational, one can use the actual value of a variable as an estimate of what agents had expected. This device can be used to obtain consistent estimates of the parameters of the partial adjustment model.]

We study two-player pie-splitting games in which one player knows the pie and the other knows only its probability distribution. We compare treatments in which incentive-efficient strikes (disagreements) are possible with alternatives in which efficiency forbids strikes. We find that incentive-efficiency is very helpful in explaining when strikes occur. There is also evidence of substantial heterogeneity in the subjects' altruism and in their risk preferences. This means that the common-knowledge assumptions of game theory cannot be controlled in experiments; but in our experiments the main theoretical conclusions seem robust to violations of these assumptions.

The Lagos‐Wright model—a monetary model in which pairwise meetings alternate in time with a centralized meeting—has been extensively analyzed, but always using particular trading protocols. Here, trading protocols are replaced by two alternative notions of implementability: one that allows only individual defections and one that also allows cooperative defections in meetings. It is shown that the first‐best allocation is implementable under the stricter notion without taxation if people are sufficiently patient. And, if people are free to skip the centralized meeting, then lump‐sum taxation used to pay interest on money does not enlarge the set of implementable allocations.

This paper develops a tractable econometric model of optimal migration, focusing on expected income as the main economic influence on migration. The model improves on previous work in two respects: it covers optimal sequences of location decisions (rather than a single once-for-all choice) and it allows for many alternative location choices. The model is estimated using panel data from the National Longitudinal Survey of Youth on white males with a high-school education. Our main conclusion is that interstate migration decisions are influenced to a substantial extent by income prospects. The results suggest that the link between income and migration decisions is driven both by geographic differences in mean wages and by a tendency to move in search of a better locational match when the income realization in the current location is unfavorable.