Bubbles, Fads, and Stock Price Volatility Tests: A Partial Evaluation

This is a summary and interpretation of some of the literature on stock price volatility that was stimulated by Leroy and Porter (1981) and Shiller (1981a). It appears that neither small sample bias, rational bubbles nor some standard models for expected returns adequately explain stock price volatility. This suggests a role for some nonstandard models for expected returns. One possibility is "fads" models in which noise trading by naive investors is important. At present, however, there is little direct evidence that such fads play a significant role in stock price determination.

The Insensitivity of Consumption to News About Income

This paper uses a variance bounds test to see whether consumption is too sensitive to news about income to be consistent with a standard permanent income model, under the maintained hypothesis that income has a unit root. It is found that, if anything, consumption is less sensitive than the model would predict. This implication is robust to the representative consumer having private information about his future income that the econometrician does not have, to wealth shocks, and to transitory consumption. This suggests the importance in future research on the model of allowing for factors that tend to make consumption smooth.

Evidence From Seven Countries on Whether Inventories Smooth Aggregate Output

Casual examination of annual postwar data on inventories and aggregate output for seven developed countries -- Canada, France, West Germany, Italy, Japan, United Kingdom, United States -- suggests that in these countries the primary function of aggregate inventories is not to smooth aggregate output in the face of aggregate demand shocks. Japan is a possible exception to this generalization.

Assessing simple policy rules: a view from a complete macroeconomic model (commentary)

Macroeconomics ; Econometric models

On the Interpretation of Near Random-Walk Behavior in GNP

It is shown that GNP will have an autoregressive root very close to unity in a variant of Taylor's (1980a,b) overlapping wage contracts model, for stylized versions of simple money supply rules and plausible values for the model's parameters. In this variant, monetary policy is the only reason for serial correlation in GNP. It is premature, therefore, to conclude, as some authors, have, that the presence of such a root in U.S. GNP is inconsistent with either a stationary natural rate or with nominal shocks playing a major role in the business cycle.

A Variance Bounds Test of the Linear Quardractic Inventory Model

This paper develops and applies a novel test of the Holt, et al.(1961) linear quadratic inventory model. It is shown that a central property of the model is that a certain weighted sum of variances and covariances of production, sales and inventories must be nonnegative. The weights are the basic structural parameters of the model. The model may be tested by seeing whether this sum in fact is nonnegative. When the test is applied to some non-durables data aggregated to the two-digit SIC code level, it almost always rejects the model, even though the model does well by traditional criteria.