Author Contributions: Dr McCahill 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: McCahill, Aiello Bowles, Single, Feigelson, James, Engel, Onitilo.
Acquisition of data: Aiello Bowles, Single, Feigelson, Barney, James, Engel, Onitilo.
Analysis and interpretation of data: McCahill, Aiello Bowles, Single, Feigelson, James, Onitilo.
Drafting of the manuscript: McCahill, Aiello Bowles, Single, Onitilo.
Critical revision of the manuscript for important intellectual content: McCahill, Aiello Bowles, Single, Feigelson, Barney, James, Engel, Onitilo.
Statistical analysis: Single.
Obtained funding: McCahill, Aiello Bowles, Single, Feigelson, James, Onitilo.
Administrative, technical, or material support: Barney, Engel, Onitilo.
Study supervision: McCahill, Aiello Bowles, Feigelson, James.
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 work was funded by grant 1RC1CA145402-01 from the American Recovery and Reinvestment Act of 2009 by the National Institutes of Health.
Role of the Sponsor: The funding source had no role in the design and conduct of the study, in the collection, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.
Online-Only Material: The Author Video Interview is available here.
Additional Contributions: Turner Osler, MD, PhD (University of Vermont), provided helpful discussions regarding the modeling of surgeon level variation; Johanna Sheehey-Jones, RN (Fletcher Allen Health Care), provided training of institutional medical abstractors for the project; and Marie Fleisner (Marshfield Clinic Research Foundation's Office of Scientific Writing and Publication) provided editorial assistance with the manuscript. Dr Osler and Ms Fleisner received no compensation for their contributions. Ms Sheehey-Jones received partial salary support in her efforts of training abstractors by the National Institutes of Health grant.