I appreciate the opportunity to clarify some points made in my editorial on the mammography controversy. I will address Drs. Berg, Allan, and Woolf's points in reverse order. My mention of alternative approaches to representing uncertainty was not a criticism of the USPSTF methods; indeed, the USPSTF has been a leader in developing methods to translate evidence into policy recommendations. But the USPSTF has changed its methods over time (1), and I assume that methodologic progress will continue. My suggestion—not a "faulting"—was aimed at moving the USPSTF and the field toward different means of representing uncertainty.

Regarding Berg and colleagues' second point, I did not state that the empirical evidence from 400 000 women is worth little more than "an expert's guesses." I said that "the justification for why studies are included or excluded from the evidence base can rest on competing claims of methodologic authority that look little different from the traditional claims of medical authority that proponents of evidence-based medicine have criticized." The USPSTF documents stated only that the study flaws introduced biases that were "unlikely" or "inadequate" to account for the observed effects. These are expressions of opinion, expert though they may be. I do not criticize such opinions, but I do take issue with claims or implications that they are absent when evidence-based methods are used.

The first issue Berg and colleagues raise is the most critical and may be an area in which we will remain in disagreement. I stated that their discussion of increased surgical rates was oblique. By oblique I meant not presented in a way that woman and their doctors could use in decision making, which requires knowing the actual surgical risks. Neither the Web version of their report nor the published document provide the actual surgical risks (reported by Olsen and Gøtzsche [2] as an increase of approximately 4 surgeries per 1000 screened women), nor do they explain why they are absent. Their letter and the published USPSTF rationale (3, 4) appear to imply that an elevation in surgery rates is acceptable if it produces a mortality benefit. While it is true that we would expect surgical rates to be higher in a mammographically screened group, the central question for physicians and for each woman (particularly those younger than 50) is whether the (possible) mortality benefit is worth these surgical risks, which exist in addition to risk for extra biopsies and anxiety due to false-positive results. Without numbers, that is hard to judge.