False Negatives on the BRFSS Disability Questions: Implications for Disability Services and Policy

Objective: Accurate measurement of disability prevalence remains a public health challenge. Behavioral Risk Factor Surveillance System (BRFSS) data are used to identify emerging health problems, develop public health initiatives, and examine health disparities among people with disabilities. On the other hand, the Social Security Administration's (SSA) more stringent definition of disability sets the standard for accessing federal disability benefits. The purpose of this study was to examine the validity and sensitivity of the BRFSS disability questions among individuals with SSA-determined disabilities, i.e., people who have severe disabilities that prevent them from engaging in substantial gainful activity. Methods: The two BRFSS disability screening questions were asked in a 2009 survey of 375 Kansas adults, 100% of whom had Social Security-determined disabilities. Results: Only 81% of the surveyed Kansans with disabilities responded affirmatively to one or both of the BRFSS disability questions (true positives). People with self-reported mental illness or intellectual disabilities, including some who required attendant care, accounted for most of the remaining 19% (false negatives). Conclusions: This high rate of false negatives suggests the need to carefully examine current disability measures used by the BRFSS, while studying the resultant public health policy implications. Because BRFSS disability questions are used not only to measure prevalence, but to project the need for future funding and service initiatives, it is essential that prevalence of people with disabilities—particularly those with more severe disabilities—not be underestimated. The International Classification of Disability, Functioning and Health (ICF) provides a possible framework for alternate question development.