This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the NRC’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:

Julie Gilchrist, M.D., National Center for Injury Prevention and Control, Centers for Disease Control, Atlanta, Georgia

Stephen H. Hauser, M.D., Department of Neurology, University of California at San Francisco, San Francisco, California

Mark R. Lovell, M.D., Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania

Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the final draft of the report before its release. The review of this report was overseen by Richard Frank, Harvard Medical School. Appointed by the National Research Council and Institute of Medicine, he was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authors and the institution.