The Heckman sample selection model relies on the assumption of normal and homoskedastic disturbances. However, before considering more general, alternative semiparametric models that do not need the normality assumption, it seems useful to test this assumption. Following Meijer and Wansbeek...

Many economic panel and dynamic models, such as rational behavior and Euler equations, imply that the parameters of interest are identified by conditional moment restrictions. We introduce a novel inference method without any prior information about which conditioning instruments are weak or...

This paper presents a consistent GMM residuals-based test of functional form for time series models. By relating two moments we deliver a vector moment condition in which at least one element must be non-zero if the model is mis-specified. The test will never fail to detect mis-specification of...