RT Journal A1 Rudin RS T1 The litmus test for health information exchange success: Will small practices participate?: comment on “health information exchange” JF Archives of Internal Medicine JO Archives of Internal Medicine YR 2010 FD April 12 VO 170 IS 7 SP 629 OP 630 DO 10.1001/archinternmed.2010.59 UL http://dx.doi.org/10.1001/archinternmed.2010.59 AB The movement to establish widespread health information exchange (HIE) in the United States has thus far shown mixed results.1 Although the number of sustainable HIEs is increasing, it appears that few of them encompass a large enough portion of health care providers and patients to significantly affect the provision of care. Even long-standing and eminently successful HIEs have been slow to gather clinical data from independent office-based practices,2 which account for most health care use in the United States.3 In addition, not much is known about the extent to which existing HIEs organize clinical data as patient-centric, longitudinal records accessible to all health care providers caring for a patient. Many HIEs achieve sustainability by automating the provision of test results1 rather than offering more robust data-exchange functionality in which physicians can actually view a wide array of clinical data generated by other physicians, formatted as a unified record for each patient. Understanding why physicians, especially those who are office based, do or do not participate in HIE has become more urgent now to inform the ways the American Recovery and Reinvestment Act's payments for meaningful use of HIE can be effectively targeted.