Stata Help

estat hettest

Stata has the following to say on the subject of the estat hettest "estat hettest performs three versions of the Breusch-Pagan (1979) and Cook-Weisberg (1983) test for linear heteroskedasticity. All three versions of this test test against the null hypothesis that the error variances are all equal. In the normal version, performed by default, the null hypothesis also includes the assumption that the regression disturbances are independent-normal draws with variance sigma^2. The normality assumption is dropped from the null hypothesis in the iid and fstat versions, which respectively produce score and F tests. If varlist is not specified, the fitted values are used for z. If varlist or the rhs option is specified, the variables specified are used for z."

The syntax itself is simply estat hettest [variable1] [variableN] and can take a number of options. See Stata's official help for more information.

A low chi-square (and correspondingly high p-value) imply that the error variance is not heteroskedastic enough to cause problems with your test statistics.