INTRODUCTIONTraumatic Brain Injury Rehabilitation ComparativeEffectiveness Research: Introduction to the TraumaticBrain InjuryePractice Based EvidenceArchivesSupplementSusan D. Horn, PhD,aJohn D. Corrigan, PhD,bMarcel P. Dijkers, PhDcFrom theaInstitute for Clinical Outcomes Research, International Severity Information Systems, Salt Lake City, UT;bDepartment of PhysicalMedicine and Rehabilitation, Ohio State University, Columbus, OH; andcDepartment of Rehabilitation Medicine, Icahn School of Medicine atMount Sinai, New York, NY.Current affiliation for Horn, Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City, UT.AbstractThis supplement of theArchives of Physical Medicine and Rehabilitationis devoted to the Traumatic Brain InjuryePractice Based Evidencestudy, the first practice-based evidence study, to our knowledge, of traumatic brain injury rehabilitation. The purpose of this preface is toplace this study in the broader context of comparative effectiveness research and introduce the articles in the supplement.Archives of Physical Medicine and Rehabilitation 2015;96(8 Suppl 3):S173-7ª2015 by the American Congress of Rehabilitation MedicineThis supplement of theArchives of Physical Medicine and Reha-bilitationoffers an initial set of results and analyses of the TBI-PBE study, funded by the National Institutes of Health, NationalInstitute on Disability and Rehabilitation Research, and OntarioNeurotrauma Foundation. It is the first practice-based evidencestudy, to our knowledge, of traumatic brain injury (TBI) rehabili-tation. Practicing therapists provided detailed documentation oftherapy sessions, and this information was combined with medicalrecord abstracted data, downloaded medication data, surveys ofpatients’ postdischarge outcomes, and clinician profiles of theirtraining and experience in rehabilitation, in general, and with TBIspecifically. The purpose of this preface is to place this study in thebroader context of comparative effectiveness research (CER) andintroduce the articles in the supplement, which offer conclusionsbased on what we believe is the richest dataset on TBI rehabili-tation ever assembled.The ProblemThe Centers for Disease Control and Prevention (CDC) estimatedthat in 2010 approximately 2.5 million people in the United Statessustained a TBI.1Of these, 2.2 million had emergency departmentvisits, 280,000 were hospitalized and survived, and 52,000 died.1,2The Brain Injury Association of America and researchers at theCDC estimated that 3.1 to 5.3 million people in the United Stateslive with long-term disability arising from physical, emotional, orcognitive consequences of TBI.3-5Although the personal and fa-milial consequences of TBI are devastating, so are the financialimplications. In 2010, the CDC estimated that the annual cost tosociety of TBI for direct medical care, rehabilitation, and indirectcosts (eg, lost productivity) totaled>$76.5 billion, with 90% ofthese costs attributed to severe injury.