Yi = a + b*Xi + ei

For the second regress the squared errors on other variables, testing to see if there is a relationship between these estimated residual "variances" and the other variables. If you want to do the Breusch-Pagan test you run:

ei2/2 = g + d*Zi + ui

If you want to do the White test you run:

ei2 = g + d*Zi + ui

You can do either test easily with TSP. After the first regression retrieve the residuals @RES and square them, then regress the new series on Z. For the Breusch-Pagan test you will also need the variance of the residuals @S2.

To compute the Breusch-Pagan divide the sum of squares for the second regression (RSS) by 2. The RSS can easily be obtained by multiplying the R2 by TSS, the total sum of squares. Note that since R2 is equal to RSS/TSS, RSS=@RSQ*@SSR/(1-@RSQ)). On the other hand, to carry out the White test you multiply the number of observations by the R2 (@NOB*@RSQ). We compute both tests in Example 6.3.


Note that TSP version 4.4 automatically supplies a version of the White test where Zi is the squared fitted values for Yi in the regression output, as a general omnibus heteroskedasticity test.