Patient characteristics of provider survey respondents: no evidence of nonresponse bias.

Surveys of physicians are an important tool to assess opinions and self-reported behaviors of this policy-relevant population. However, this population is notoriously difficult to survey and plagued with low and falling response rates. In order to evaluate the potential import of response rate, we examine the presence of nonresponse bias in a survey of physicians providing diabetes care that achieved a 36% response rate. Unlike other studies examining differences in individual characteristics for responding and nonresponding physicians, we also assess differences with respect to aggregate patient demographic, clinical, and behavioral characteristics. We are unable to demonstrate nonresponse bias, even with what could be construed as a relative low response rate. Nonetheless as the threat of nonresponse bias can never be completely assuaged, we believe that it should be monitored as a matter of course in physician surveys and offer a new dimension by which it can be evaluated.