Knowledge that Transforms

This paper suggests that decision-making under uncertainty is, at least partly, case-based. We propose a model in which cases are primitive, and provide a simple axiomatization of a decision rule that chooses a “best” act based on its past performance in similar cases. Each act is evaluated by the sum of the utility levels that resulted from using this act in past cases, each weighted by the similarity of that past case to the problem at hand. The formal model of case-based decision theory naturally gives rise to the notions of satisficing decisions and aspiration levels.

A model of the labor market under firing restrictions and endogenous quits is constructed. It is shown that in the spirit of Blanchard and Summers, the model can generate multiple equilibria for plausible parameter values, with a low quits/high unemployment equilibrium coexisting with a high quits/low unemployment equilibrium.

Market responses to legislative reforms often mitigate the expected gains that reformers promise in legislation. Contemporaries hailed workers' compensation as a boon to workers because it raised the amount of postaccident compensation paid to injured workers. Despite the large gains to workers, employers often supported the legislation. Analysis of several wage samples from the early 1900s shows that employers were able to pass a significant part of the added costs of higher postaccident compensation on to some workers in the form of reductions in wages. The size of the wage offsets, however, was smaller for union workers.

This paper shows that previous analyses of IRA-type plans that seek to encourage household saving have miscalculated their effect on tax revenue and therefore on national saving by ignoring their favorable impact on corporate tax payments. Recognizing the important effects of IRA plans on corporate tax revenue changes previous conclusions about the revenue loss in a fundamental way. The revenue loss associated with IRAs either is much smaller than has generally been estimated or is actually a revenue gain.

This paper proposes a theory of supply shocks, or shifts in the short-run Phillips curve, based on relative-price changes and frictions in nominal price adjustment. When price adjustment is costly, firms adjust to large shocks but not to small shocks, and so large shocks have disproportionate effects on the price level. Therefore, aggregate inflation depends on the distribution of relative-price changes: inflation rises when the distribution is skewed to the right, and falls when the distribution is skewed to the left. We show that this theoretical result explains a large fraction of movements in postwar U. S. inflation. Moreover, our model suggests measures of supply shocks that perform better than traditional measures, such as the relative prices of food and energy.

Decisions under uncertainty depend not only on the degree of uncertainty but also on its source, as illustrated by Ellsberg's observation of ambiguity aversion. In this article we propose the comparative ignorance hypothesis, according to which ambiguity aversion is produced by a comparison with less ambiguous events or with more knowledgeable individuals. This hypothesis is supported in a series of studies showing that ambiguity aversion, present in a comparative context in which a person evaluates both clear and vague prospects, seems to disappear in a noncomparative context in which a person evaluates only one of these prospects in isolation.

This paper investigates the effects of shocks to U. S. monetary policy on exchange rates. We consider three measures of these shocks: orthogonalized shocks to the federal funds rate, orthogonalized shocks to the ratio of nonborrowed to total reserves and changes in the Romer and Romer index of monetary policy. In sharp contrast to the literature, we find substantial evidence of a link between monetary policy and exchange rates. Specifically, according to our results a contractionary shock to U. S. monetary policy leads to (i) persistent, significant appreciations in U. S. nominal and real exchange rates and (ii) significant, persistent deviations from uncovered interest rate parity in favor of U. S. interest rates.

This paper demonstrates that the behavior of the conventional Phelps-Taylor model of overlapping wage contracts stands in stark contrast with important features of U. S. macro data for inflation and output. In particular, the Phelps-Taylor specification implies far too little inflation persistence. We present a new contracting model, in which agents are concerned with relative real wages, that is data-consistent. In a specification that nests both models, we resoundingly reject the conventional contracting model, but cannot reject the new contracting model.

Wholesale trade in used cars is conducted by ascending bid auctions, with sale subject to the seller's acceptance of the winning bid. One out of three times the seller rejects the bid, and no trade takes place. I model the seller's decision as the outcome of search, and thus determined by the winning bid distribution, and a reported retail price. This market is ideal for testing search theory since all offers, whether or not accepted, are observed. Qualitative predictions of the theory, in particular the role of the variance, are confirmed. The quantitative results are more ambiguous. One out of every three times, seller and buyer fail to trade at wholesale auto auctions. Instead, the seller exercises his right to refuse the winning bid. This paper shows how search theory can explain the sale rate and its variation across different types of automobiles. Few readers will find intrinsic interest in wholesale auto auctions. The value to studying them lies instead in the opportu-nity to observe all offers to trade in an environment that neatly