We thank the readers for their many comments and welcome the opportunity to clarify our processes and recommendations. Dr. Dean, by focusing on estimates of the number needed to invite for screening, implies that these estimates were the sole determinant of the USPSTF's conclusion that the net benefit of starting mammography screening in women in their 40s is small compared with starting at a later age. In fact, such information was only one of several lines of evidence that we considered. The analysis of Breast Cancer Surveillance Consortium (BCSC) data, information about the risks of radiation and overdiagnosis, and the Cancer Intervention and Surveillance Modeling Network (CISNET) study also contributed. Dr. Braithwaite may be correct that the USPSTF's rationale for when to start screening was left too open to interpretation; however, it is incorrect for anyone to assume that the USPSTF used (or has ever used) NNS as a backdoor means of rationing care.