Decision makers want to know which healthcare services matter the most, but there are no well-established, practical methods for providing evidence-based answers to such questions. Led by the National Commission on Prevention Priorities, the authors update the methods for determining the relative health impact and economic value of clinical preventive services. Using new studies, new preventive service recommendations, and improved methods, the authors present a new ranking of clinical preventive services in the companion article. The original ranking and methods were published in this journal in 2001. The current methods report focuses on evidence collection for a priority setting exercise, guidance for which is effectively lacking in the literature. The authors describe their own standards for searching, tracking, and abstracting literature for priority setting. The authors also summarize their methods for making valid comparisons across different services. This report should be useful to those who want to understand additional detail about how the ranking was developed or who want to adapt the methods for their own purposes.