AbstractThis paper looks at the issue once more of whether there is a statistically significant relationship between industry structure and economic performance. Tempered by the results of a test for structural stability, it is suggested that judicious choice of the industries included in the sample used to estimate the hypothesized relationship will lead to any desired result. As a consequence, one must be cautious in accepting the results of any study that unequivocally purports to show the presence or absence of an identifiable relationship between industry structure and industry performance.