We are grateful to Hidetoshi Saito for his careful and reasoned critique of the VARBRUL procedure in his article, “Dependence and Interaction in Frequency Data Analysis in SLA Research” (this issue). Saito reanalyzes Young's (1988, 1991) study of -s plural variation in the English interlanguage of native speakers of Chinese. He raises two criticisms of the statistical analyses in the original work: (a) data from all participants were lumped together, resulting in an analysis that ignores possible variation across participants; and (b) interaction between independent variables was not investigated, whereas Saito finds that an interaction term contributes to a statistical model that fits the data better than the original analysis.