Testing Parameter Constancy and Super Exogeneity in Econometric Equations.

The paper is concerned with testing super exogeneity in a single equation that can either be linear or partially nonlinear. A joint test for testing both weak exogeneity and a form of invariance, which together amount to a form of super exogeneity, is presented and its properties discussed. The considerations also include testing parameter constancy and modeling parameter nonconstancy prior to testing super exogeneity. The practical application of the tests is demonstrated by an example in which testing super exogeneity in a consumption function for Norway, based on a previously published model is considered. The results are compared with the previous conclusions and found not to disagree with them. Copyright 1996 by Blackwell Publishing Ltd