Representativeness of PBRN physician practice patterns and related beliefs: the case of the AAFP National Research Network.

PURPOSE: We wanted to compare survey responses from members of a national practice-based research network (PBRN) with those of a larger sample of family physicians to assess the generalizability of findings from the PBRN to the larger physician population.
METHODS: The American Academy of Family Physicians National Research Network (AAFP NRN) conducted 3 separate national surveys among random samples of AAFP active members and physician members of the AAFP NRN. The surveys assessed self-reported clinical behaviors and beliefs related to hepatitis C, hyperlipidemia, and pharyngitis. Bivariate comparisons were conducted to detect statistical differences between the AAFP and AAFP NRN respondents on both demographic and clinically relevant survey items. Multivariate analyses of outcomes were found to be statistically significant at the bivariate level.
RESULTS: Response rates to the surveys ranged from 53% to 59% for AAFP members and 60% to 72% for AAFP NRN members. The most consistent differences (P <.05) in demographic comparisons were for percentage of time spent in patient care, practice location, practice type, and census region. Bivariate comparisons found the groups differed on 8 (12%) of 66 clinically relevant survey items, with the Bonferroni correction for multiple comparisons reducing these items to 4 (6%). These comparisons were followed by multivariate analyses of outcomes that were found statistically significant at bivariate level.
CONCLUSIONS: The AAFP NRN and AAFP membership differed on several demographic characteristics, but network members were overall more representative than not of the AAFP active membership in their self-reported clinical behaviors and related beliefs.