Using multiple survey vendors to collect health outcomes information: How accurate are the data?

BACKGROUND: To measure and assess health outcomes and quality of life at the national level, large-scale surveys using multiple vendors to gather health information is becoming the norm. This study evaluates the ability of multiple survey vendors to gather and report data collected as part of the 1998 Medicare Health Outcomes Survey (HOS). METHOD: Four hundred randomly sampled completed mailed surveys were chosen from each of six certified vendors (N = 2397) participating in the 1998 HOS. The accuracy of the data gathered from the vendors was measured by creating a "gold standard" record for each survey and comparing it to the final record submitted by the vendor. RESULTS: Overall rates of agreement were calculated, and ranged from 97.0% to 99.8% across the vendors. CONCLUSION: Researchers may be confident that using multiple vendors to gather health outcomes information will yield accurate data.