In statistics,the White test is a statistical test that establishes whether the residual variance of a variable in a regression model is constant (homoscedasticity).To test for constant variance one regresses the squared residuals from a regression model onto the regressors,the cross-products of the regressors and the squared regressors.One then inspects the R2.If homoscedasticity is rejected one can use a GARCH model.
This test,and an estimator for heteroscedasticity-consistent standard errors,were proposed by Halbert White in 1980.These methods have become extremely widely used,making this paper one of the most cited articles in economics