Current Population Survey
The Current Population Survey (CPS) is a monthly survey that provides current estimates and trends in employment, unemployment, earnings, and other characteristics of the general labor force, the population as a whole, and various population subgroups.
The basic CPS sample is selected from multiple frames using multiple stages of selection. The sample design is state-based, with the sample in each state being independent of the others. One person generally responds for all household members. Employment information is collected on the job held in the reference week, defined as the 7-day period, Sunday through Saturday, that includes the 12th of the month. Labor force data are published only for persons aged 16 and older; no upper age limit is used. Full-time students are treated the same as nonstudents. The March CPS supplement is expanded to include Armed Forces members living in a household that includes at least one civilian and additional Hispanic households that are not included in the monthly labor force estimates. The additional Hispanic sample is drawn from the previous November's basic CPS sample. All CPS data files are weighted; information on weighting procedures is available in the Technical Documentation section of the CPS website.
Prior to 2001, the basic CPS sampled 50,000 households a month. Beginning with 2001, with the introduction of the Children's Health Insurance Program (CHIP) sample, the basic CPS monthly sample was expanded to 60,000 households. The average monthly nonresponse rate for the basic CPS is about 7%-8%.
National Center for Health Statistics. Health United States 2009: With Special Feature on Medical Technology. Hyattsville, Maryland. 2010; pp 450-452.