Research Database

This paper evaluates Hayashi's conjecture that Japan's postwar saving experience can be accounted for by the neoclassical model of economic growth as that country's efforts to reconstruct its capital stock that was severely damaged in World War II. I call this the reconstruction hypothesis. I take a simplified version of a standard neoclassical growth model that is in widespread use in macroeconomics and simulate its response to capital destruction. The saving rate path implied by the model differs significantly from the path taken by actual Japanese postwar saving data. I discuss several model modifications which would reconcile the reconstruction hypothesis with Japan's postwar saving experience. For the reconstruction hypothesis to be credible requires independent evidence on the empirical plausibility of the model modifications. It is left to future research to determine whether that evidence exists.

This article describes the current state of economic theory intended to explain the unequal distribution of wealth among U.S. households. The models reviewed are heterogeneous agent versions of standard neoclassical growth models with uninsurable idiosyncratic shocks to earnings. The models endogenously generate differences in asset holdings as a result of the household's desire to smooth consumption while earnings fluctuate. Both of the dominant types of models—dynastic and life cycle models—reproduce the U.S. wealth distribution poorly. The article describes several features recently proposed as additions to the theory based on changes in earnings, including business ownership, higher rates of return on high asset levels, random capital gains, government programs to guarantee a minimum level of consumption, and changes in health and marital status. None of these features has been fully analyzed yet, but they all seem to have potential to move the models in the right direction.

The paper employs three different types of identifying restrictions to calculate the impulse responses for the trivariate series composed of the U.S. unemployment level, real GNP and the money stock. The first two are the zero restrictions, arising from the assumption of the delayed information pattern available in forming a money reaction function. The third assumes a particular simplified structural model. The paper shows that the impulse response patterns are generally insensitive to these alternative specifications. Similar exercises are carried out for the bivariate series composed of the U.S. and the unemployment level.