Heterogeneous effects are prevalent in many economic settings. As the functional form between outcomes and regressors is generally unknown a priori, a semiparametric negative binomial count data model is proposed which is based on the local likelihood approach and generalized product kernels....

In the presence of heteroskedasticity, conventional standard errors (which assume homoskedasticity) can be biased up or down. The most common form of heteroskedasticity leads to conventional standard errors that are too small. When Wald tests based on these standard errors are insignificant,...

This paper demonstrates that popular linear fixed-effects panel-data estimators are biased andinconsistent when applied in a discrete-time hazard setting - that is, one in which the outcomevariable is a binary dummy indicating an absorbing state, even if the data-generating process isfully...