Life-cycle models of labor supply predict the presence of an unobserved individual effect in the labor-supply equation that is correlated with observed explanatory variables, leading to an omitted variables bias in the cross section. The author examines the sensitivity of parameter estimates to...

The influential Scherer and Ross text (1990, p. 411) states that the ?main question? in empirical industrial organization in the latter part of the twentieth century is Bain?s (1951) ?collusion? or ?agreement? hypothesis versus Demsetz?s (1973) ?superior firm? hypothesis. Prior to the Federal...