This paper examines disability as measured and reported in three Census surveys: the American Community Survey (ACS), the Current Population Survey (CPS), and the Survey on Income Program Participation (SIPP). We focus on whether person-specific disability, as measured by the Census, is a permanent or a transitory condition. Survey data results regarding the incidence of Census-measured disability are shown both cross-sectionally and longitudinally. It is found from longitudinal CPS and SIPP responses that Census-measured disability is largely transitory. That finding empirically confirms the longstanding theoretical objections to the use of Census cross-section disability data along with a permanent disability assumption in worklife expectancy models; hence, any worklife expectancy model which assumes that Census disability measures are permanent conditions is misspecified and empirically invalid. Instead of using the permanent disability assumption, we use actual longitudinal disability transition probabilities and life table analysis to quantify the lifetime duration of disability as measured by the Census in total life years and working life years. We show that the realistic feature of disability transition dramatically lowers the effect of disability on worklife expectancy.