Published Online: December 1, 2014. doi:10.1001/jamainternmed.2014.6291.
Study concept and design: Gray, Gao, McCullough, Lipner.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Gray, Vandergrift, McCullough, Lipner.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Gray, Vandergrift, McCullough, Lipner.
Administrative, technical, or material support: Vandergrift, Gao, Lipner.
Study supervision: Gray, Lipner.
Conflict of Interest Disclosures: Drs Gray and Lipner and Mr Vandergrift are paid employees at the American Board of Internal Medicine.
Funding/Support: The American Board of Internal Medicine provided financial and material support for this study. This study was partially supported by National Science Foundation Career Award 1254021 (Dr Gao).
Role of the Funder/Sponsor: The American Board of Internal Medicine had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.