Nonnormalities and Tests of Asset Pricing Theories.

Abstract

The robustness of the multivariate tests of Michael R. Gibbons, Stephen A. Ross, and Jay Shanken (1986) to nonnormalities in the residual covariance matrix is examined. After considering the relative performance of various tests of normality, simulation techniques are used to determine the effects of nonnormalities on the multivariate tests. It is found that, where the sample nonnormalities are severe, the size and/or power of the test can be seriously misstated. However, it is also shown that these extreme sample values may overestimate the population parameters. Hence, they conclude that the multivariate test is reasonably robust with respect to typical levels of nonnormality. Copyright 1989 by American Finance Association.