To the Editor: Dr. Quitkin and colleagues suggest that the gender differences in response rates we reported are artifacts of a difference in dropout rates, and they use their own completer analysis to support this. Their point is well taken that if one performs only a completer analysis of rates of response to sertraline and imipramine treatment by gender, the differences are less strong. However, their reanalysis is based on incorrect data. The response rates for the completers were actually 69.5% (41 of 59) for the men taking imipramine, 55.3% (68 of 123) for the men taking sertraline, 56.0% (56 of 100) for the women taking imipramine, and 60.4% (137 of 227) for the women taking sertraline. (Not all dropouts were nonresponders.) Moreover, Dr. Quitkin et al. compare only three out of four response rates, which is an inappropriate analysis for a 2×2 factorial design. The appropriate analysis for this design is to test the two main effects and then the interaction between the two. If there is a significant interaction, then the comparisons of the main effects are not valid alone. For the completers, a test of interaction evaluating the pattern of response to the two drugs by men and women was statistically significant (Wald χ2=4.82, df=1, p=0.03), as reported in our article.