Author Contributions: Drs Colla and Gottlieb had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Wennberg, Meara, Gottlieb, Snyder, Fisher, Colla.
Acquisition of data: Skinner, Fisher.
Analysis and interpretation of data: Wennberg, Meara, Skinner, Gottlieb, Snyder, Colla.
Drafting of the manuscript: Gottlieb, Fisher, Colla.
Critical revision of the manuscript for important intellectual content: Wennberg, Meara, Skinner, Gottlieb, Snyder, Fisher, Colla.
Statistical analysis: Skinner, Gottlieb, Snyder, Colla.
Obtained funding: Skinner, Fisher.
Administrative, technical, or material support: Fisher, Colla.
Study supervision: Meara, Colla.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: This research was funded by grant NIA P01AG19783 from the National Institute on Aging, the Dartmouth Atlas Project (supported by a consortium led by the Robert Wood Johnson Foundation), and the Commonwealth Fund.
Role of the Sponsor: None of the funders had a role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.
Additional Contributions: We thank Harold Sox, MD, of Dartmouth Medical School for helpful comments on the manuscript for which he received no compensation.
This article was corrected for errors on September 11, 2012.