This paper proposes a speci.cation test of the mixed logit models, by generalizing Haus- man and McFadden.s (1984) test. We generalize the test even further by considering a model developed by Berry, Levinsohn and Pakes (1995).

Panel or grouped data are often used to allow for unobserved individual heterogeneity in econometric models via fixed effects. In this paper, we discuss identification of a panel data model in which the unobserved heterogeneity both enters additively and interacts with treatment variables. We...