Author Contributions: Dr Steiner 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: Brousseau, Owens, Panepinto, Steiner.
Acquisition of data: Mosso, Steiner.
Analysis and interpretation of data: Brousseau, Owens, Mosso, Steiner.
Drafting of the manuscript: Brousseau, Owens.
Critical revision of the manuscript for important intellectual content: Owens, Mosso, Panepinto, Steiner.
Statistical analysis: Owens, Mosso, Steiner.
Administrative, technical, or material support: Steiner.
Study supervision: Brousseau, Panepinto.
Financial Disclosures: None reported.
Funding/Support: Work on this study was funded in part by a Career Development Award (D.C.B.) from the Agency for Healthcare Research and Quality.
Role of the Sponsor: The funding organization 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.
Disclaimer: The views expressed in this article are those of the authors and do not necessarily represent those of the Agency for Healthcare Research and Quality or the US Department of Health and Human Services.
Additional Contributions: Data organizations in 8 states contributed data to the Healthcare Cost and Utilization Project (HCUP), which we used in this study: Arizona Department of Health Services, California Office of Statewide Health Planning and Development, Florida Agency for Health Care Administration, Massachusetts Division of Health Care Finance and Policy, Missouri Hospital Industry Data Institute, New York State Department of Health, South Carolina State Budget and Control Board, and Tennessee Hospital Association. Mark Nimmer, BA, Research Assistant, Department of Pediatrics, Medical College of Wisconsin, helped with manuscript preparation. He received no separate compensation for his help.