This variable indicates that a person had a work-preventing disability at time t where t = a (earlier wave) or b (later wave). If an individual indicates a work-preventing disability in wave 2, disab_nowork_a = 1. In all panels but 1984, this question is asked again in a later wave: individuals indicating a work-preventing disability in that question have disab_nowork_b = 1. The universe is all individuals who were at least age 15, no older than age 70 by the end of the panel, and answered "yes" to having a work-limiting disability. The relevant SIPP variable for disab_nowork_a is TM8332 for the 1990-1993 panels and eprevwk for the 1996, 2001, 2004, and 2008 panels. For disab_nowork_b, the relevant SIPP variable is TM8924 in the topical module for the 1990-1993 panels and edisprev in the core of the 1996, 2001, 2004, and 2008 panels. The variable comes from wave 3 for 1990, 1991, and 1993; wave 5 for 1996, 2001, and 2004; and wave 6 for 1992 and 2008.