THE THICK VOLUME under review, by Richard Layard, Stephen Nickell, and Richard Jackman, is an extensive econometric and theoretical study, using time-series and cross section data, of the central tendency of the unemployment rate and its fluctuations in 19 OECD countries since the mid-50s. It thus joins the company of several recent macroeconometric studies of employment determination using international time-series data. Of these it is easily the most far-ranging study to date though in its microscopic examination of social legislation it has somehow neglected a range of macro factors right under its nose. Readers will find an abundance of arresting claims and provocative positions to keep the critical juices flowing. For me the volume is significant not (or hardly at all) as an assemblage of particular modelings and findings but primarily as an early econometric expression of the paradigm shift we are now witnessing in macroeconomics. Once nearly made extinct by a neoclassical winter, a school of economists are today furiously at work on unemployment considered as an equilibrium phenomenon' springing from en-

The commitment value of financial contracts is limited by the ability of contracting parties to renegotiate them away, if it becomes mutually beneficial to do so. When debt contracts are used by oligopolistic firms to commit to aggressive output strategies as in Brander-Lewis, we show that renegotiation may undermine commitment under symmetric information, but not generally under asymmetric information. Lasting contracts that survive renegotiation are proposed. It is shown that there exist lasting debt contracts which preserve the commitment value and in which not all debt is renegotiated away.

The paper analytically evaluates alternative specifications of price-earnings regressions when prices lead earnings, i.e., reflect information about future earnings that is not reflected in the past time series of earnings. Because prices lead earnings, the specification using the earnings-level-deflated-by-price variable in a price-earnings regression is ‘better’, in terms of bias in the estimated earnings response coefficient and explanatory power, than specifications using earnings-change-deflated-by-price and earnings-deflated-by-lagged-earnings variables. An accurate proxy for unexpected earnings, however, outperforms the earnings-level- and earnings-change-deflated-by-price specifications.

This paper describes several learning processes which converge, with probability one, to the rational expectations (Bayesian-Nash) equilibrium of a stationary linear game. The learning processes include a test for convergence to equilibrium, and a method for changing the parameters of the process when non-convergence is indicated. This self-stabilization property eliminates the need to impose stability conditions on the economic environment. Convergence to equilibrium is proved for two types of self-stabilizing learning mechanisms: a centralized forecasting mechanism and a decentralized strategy adjustment process.

In this paper we analyze how depositors can employ both monitoring and capital requirements to control the risk of bank assets. We also analyze how monitors should be compensated if their actions are not directly observable and if there are binding limits on their liability. Second-best capital and monitoring levels (with unobservable actions) will be distorted away from their respective first-best levels. We derive some results about the nature of these distortions and characterize the optimal incentive scheme for monitors.

Though not conceived as a constant, the natural unemployment rate was taken to be invariant to supply shocks until the late seventies and to real demand shocks until now. The largely micro-theoretic model here is one in a series deriving the natural rate path from general equilibrium. In this model the labor market exhibits generalized real-wage rigidity, resulting from the use of "incentive wages" to combat shirking, and the asset backing shares is the firms' customers, arising from customer-market friction. One finding is that increased consumer demand drives up the natural rate by driving real interest rates up.

Stock return over a period reflects the market's revision in expectation of future earnings. Accounting earnings over the same period, however, have limited ability to reflect such revised expectations. Therefore, returns anticipate earnings changes and the earnings response coefficient from a regression of returns on contemporaneous earnings changes is biased toward zero. We reduce this bias by including leading-period returns in price-earnings regressions. The resulting estimated earnings response coefficient magnitudes suggest that the capital market, on average, views earnings changes to be largely permanent. This is consistent with the random walk time series property of annual earnings.

This study derives and estimates a dynamic model of factor demand that includes both fixed and quadratic variable costs of adjustment. Using quarterly data on the employment of mechanics at seven airlines, it finds that both types of adjustment costs characterize the dynamic constraints facing employers. Using monthly data covering production-worker employment in seven manufacturing plants, it shows that only fixed costs are important. The apparent diversity of the underlying costs of adjustment means it is difficult to draw useful inferences from macroeconometric estimates. It suggests the importance of examining broader arrays of microeconomic time series describing labor demand.

With grouping, a sample is sorted by an observable variable and the mean values of the dependent variable in the extreme-ranked groups are compared. We show that test power is maximized when the two extreme groups each contain 27% of the sample, a much larger percentage than that typically used in the literature. This result is not sensitive to the distribution of the dependent variable. We also show that regression is unambiguously more powerful than grouping, even when the independent variable is measured with error.