Author Contributions: Dr Goldman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Goldman, Joyce.
Acquisition of data: Goldman, Zheng.
Analysis and interpretation of data: Goldman, Joyce, Zheng.
Drafting of the manuscript: Goldman, Joyce, Zheng.
Critical revision of the manuscript for important intellectual content: Goldman, Joyce.
Statistical analysis: Goldman, Joyce, Zheng.
Obtained funding: Goldman.
Administrative, technical, or material support: Goldman.
Study supervision: Goldman, Joyce.
Financial Disclosures: None reported.
Funding/Support: This research was sponsored by the National Institute on Aging through its support of the RAND Roybal Center for Health Policy Simulation and by the Peter Bing Center for Health Economics at RAND.
Role of the Sponsors: None of the sponsors had any role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; or preparation, review, or approval of the manuscript.
Additional Contribution: We are grateful to Paul Shekelle, MD, PhD, RAND Corporation, and Veterans Affairs Health Services Research and Development Service, Los Angeles, California, for his guidance on conducting a systematic evidence review.