This study decomposes the performance of US public firms between 1981 and 1994 into year, industry, corporate-focus and firm effects. Performance is measured by Tobin’s q, accounting profitability, and a hybrid measure. The results show that firm effects were more important to performance than industry effects, although industry effects had a large permanent component. Corporate focus was not important. The stylized facts suggest that competitive advantages – that is, differences between direct competitors in the same industry – were at least as important as industry influences on performance. Industry influences were more predictable and sustainable than competitive advantages, however.