This chapter describes the current population survey (CPS) survey, and the Survey of Income and Education (SIE) survey. It discusses the method used to combine the data sets, and a description of problems with key variables and some of the adjustments made. The CPS supplements information from the decennial US Census of Population and Housing; while considerably smaller than the census, the CPS is the only comprehensive source of monthly labor market data, and serves as the source of official government statistics on employment and unemployment. The foreign born supplements include questions about country of birth of each member of the household, year of immigration, citizenship status, and country of birth and year of immigration of the parents of the adult members of the household. Both the CPS and the SIE provide sampling weights derived from known distributions specifically to make the weighted observations sum to the population in each area.