This paper describes the Washington Group project to test a short battery of disability questions developed for national censuses. The study used an unusually structured cognitive test protocol and was administered to a total of 1,290 respondents selected from convenience samples in fifteen countries in Central and South America, Asia and Africa. The test protocol consisted of the six core disability questions followed by questions designed to illustrate: (1) whether core questions were administered with relative ease; (2) how core questions were interpreted by respondents; (3) the factors considered by respondents when forming answers to core questions; and (4) the degree of consistency between responses to core questions and a set of more detailed functioning questions. Additionally, demographic and general health sections allowed for an examination of comparability, specifically, whether test questions performed consistently across all respondents, or if nationality, education, gender or socio-economic status impacted the ways in which respondents interpreted or considered each core question.
