This research investigates the effect of review rate on defect removal effectiveness and the quality of software products, while controlling for a number of potential confounding factors. Two data sets of 371 and 246 programs, respectively, from a personal software process (PSP) approach were analyzed using both regression and mixed models. Review activities in the PSP process are those steps performed by the developer in a traditional inspection process. The results show that the PSP review rate is a significant factor affecting defect removal effectiveness, even after accounting for developer ability and other significant process variables. The recommended review rate of 200 LOC/hour or less was found to be an effective rate for individual reviews, identifying nearly two-thirds of the defects in design reviews and more than half of the defects in code reviews.