In Reply: We thank Dr. Chaplin, who correctly points out that there were two articles about people with mental retardation that we did not identify in our review. Our search for articles on special populations published over the 50-year period entailed reviewing the contents of each issue—a total of about 8,000 articles. Such a manual search is quite a chore, and we think that our oversight is forgivable, especially when there are careful readers like Dr. Chaplin standing by to give constructive opinion. There were few articles that addressed this population, which makes the identification of two additional articles that much more significant.

We hasten to point out that even with the addition of the two articles, fewer than ten articles about people with mental retardation were published in the 50-year period. The authors share Dr. Chaplin's desire to stimulate interest in service provision for this population. We hope that our review and his letter will generate further exchange and publications in this underrepresented area of research.