Author Contributions: Dr Davidson 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: Davidson, Hamlat, Koepsell, Jurkovich, Arbabi.
Acquisition of data: Davidson, Hamlat, Arbabi.
Analysis and interpretation of data: Davidson, Hamlat, Rivara, Koepsell, Jurkovich, Arbabi.
Drafting of the manuscript: Davidson, Hamlat, Jurkovich, Arbabi.
Critical revision of the manuscript for important intellectual content: Davidson, Rivara, Koepsell, Jurkovich, Arbabi.
Statistical analysis: Davidson, Koepsell, Arbabi.
Administrative, technical, or material support: Hamlat, Rivara, Jurkovich, Arbabi.
Study supervision: Rivara, Koepsell, Jurkovich, Arbabi.
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 supported by National Institute of Child Health and Human Development grant 1T32HD057822-01AZ that was awarded to the Pediatric Injury Research Training Program.
Role of the Sponsor: The National Institute of Child Health and Human Development had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; or preparation, review, or approval of the manuscript.
Disclaimer: Dr Rivara, an editorial board member for JAMA, was not involved in the editorial review of or decision to publish this article.
Additional Contributions: We thank Chris Mack, MS, from the Harborview Injury Prevention and Research Center for his statistics and programming assistance and the Washington State Department of Health for data linkage. Mr Mack did not receive financial compensation for his work.