The closest equivalent to QUITSICK in IPUMS-USA is a category in the DISABWRK variable, which specifies that the individual has a "disability which prevents work." Researchers should keep in mind that this category in DISABWRK, available for the 1970, 1980, and 1990 censuses, is more restrictive than the QUITSICK variable in IPUMS-CPS. For example, a survey respondent might report having left one job due to health reasons but have taken another, less physically-demanding job; the census response indicates the health problem entirely precluding paid employment. Also, the time frame for DISABWRK is more precise, since the question asks about a current disability which prevents work. By contrast, QUITSICK asks whether an individual had ever left a job for health reasons; by the time of the survey, an individual might have fully recovered from a health problem that had forced them to leave a job in the distant past.