In this paper, we introduce a new identification and estimation strategy for partially linear regression models with a general form of unknown heteroscedasticity, that is, Y = X'β₀ + m(Z) + U and U = ...

The Hausman test evaluates the potential endogeneity of a regressor by examining an artificial regression that includes the residuals from a first-stage regression of the endogenous variable on the ...

ECONOMISTS develop economic models to explain consistently recurring relationships. Their models link one or more economic variables to other economic variables (see “What Are Economic Models,” F&D, ...