Survey of Income and Program Participation (SIPP) was initiated to gather information about income and the effectiveness of government support programs at all levels. A standard set of questions constitute the "core" of the survey, while more detailed information on specific topics are collected periodically. Data files--both core and topical--can be obtained through the National Bureau of Economic Research (NBER) web site. A chart has been constructed as a guide to which topical modules were administered in which years.
