Disability measurements: impact on research results

This article addresses the issue of whether the choice of operational definition of disability in survey research affects findings. Earlier studies have shown that different definitions cause substantial variation in prevalence rates, as well as limited agreement on the classification of subjects as disabled or not disabled. The article addresses whether this leads to differences in research outcomes. The study compares seven existing measurements of disability. The analysis is carried out using a single dataset; the 2007 survey of disabled people's living conditions in Norway (N=1652). Results are reported for subject descriptors (gender, age, marital status, characteristics of impairment), social indicators (education, income and employment), and predictors of income and employment. The impact of the definition of disability on results is found to be modest in general but with exceptions: The definition of disability clearly affects employment rates and the type and degree of impairment of people classified as disabled. Consequences for disability research are discussed