Author Contributions: Dr Volpp 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: Volpp, Rosen, Rosenbaum, Romano, Bellini, Silber.
Acquisition of data: Volpp, Even-Shoshan, Canamucio, Behringer, Silber.
Analysis and interpretation of data: Volpp, Rosen, Rosenbaum, Romano, Canamucio, Bellini, Silber.
Drafting of the manuscript: Volpp, Rosenbaum, Canamucio, Silber.
Critical revision of the manuscript for important intellectual content: Volpp, Rosen, Rosenbaum, Romano, Even-Shoshan, Bellini, Behringer, Silber.
Statistical analysis: Volpp, Rosenbaum, Romano, Canamucio, Silber.
Obtained funding: Volpp, Rosen, Silber.
Administrative, technical, or material support: Volpp, Even-Shoshan, Bellini, Behringer, Silber.
Study supervision: Volpp, Rosen, Rosenbaum, Silber.
Financial Disclosures: None reported.
Funding/Support: This work was supported primarily by grant IIR 04.202.1 from US Veterans Affairs Health Services Research and Development Service. Support was also received from grants R01 HL082637 from the National Heart, Lung, and Blood Institute and SES-0646002 from the National Science Foundation.
Role of the Sponsors: The sponsors had no role in the design and conduct of the study, in the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.
Additional Contributions: David Blumenthal, MD, Harvard Medical School; David Dinges, PhD, University of Pennsylvania School of Medicine; seminar participants at the University of Chicago and the University of Pennsylvania; and the ACGME Committee on Improving the Learning Environment provided comments on earlier drafts. Liyi Cen, MS, Philadelphia Veterans Affairs Medical Center and University of Pennsylvania, provided help as a statistical programmer employed on this project. Anee Lee, BA, Philadelphia Veterans Affairs Medical Center, provided help as a research assistant employed on this project. Drs Blumenthal and Dinges did not receive any compensation for their roles as members of the advisory board for this study.