From https://en.wikipedia.org/wiki/Current_Population_Survey
The Current Population Survey (CPS) is a monthly survey of about 60,000 U.S. households conducted by the United States Census Bureau for the Bureau of Labor Statistics (BLS). The BLS uses the data to publish reports early each month called the Employment Situation. This report provides estimates of the unemployment rate and the numbers of employed and unemployed people in the United States based on the CPS. A readable Employment Situation Summary is provided monthly. Annual estimates include employment and unemployment in large metropolitan areas.
Methodology
Approximately 60,000 households are eligible for the CPS. Sample households are selected by a multistage stratified statistical sampling scheme. A household is interviewed for 4 successive months, then not interviewed for 8 months, then returned to the sample for 4 months after that. An adult member of each household provides information for all members of the household.
As part of the demographic sample survey redesign, the CPS is redesigned once a decade, after the decennial census. The most recent CPS sample redesign began in April 2014.
Respondents are generally asked about their employment as of the week of the month that includes the 12th. To avoid holidays, this reference week is sometimes adjusted. All respondents are asked about the same week.
People are classified as employed if they did any work at all as paid employees during the reference week; worked in their own business, profession, or on their own farm; or worked without pay at least 15 hours in a family business or farm. People are also counted as employed if they were temporarily absent from their jobs because of illness, bad weather, vacation, labor-management disputes, or personal reasons.
Employment classification
People are classified as unemployed if they meet all of the following criteria:
- They were not employed during the reference week
- They were available for work at that time
- They made specific efforts to find employment during the 4-week period ending with the reference week. (The exception to this category covers persons laid off from a job and expecting recall)
The unemployment data derived from the household survey doesn't relate or depend on the eligibility of the worker to receive unemployment insurance benefits.
Those who are not classified as employed or unemployed are not counted as part of the labor force. These people—those who have no job and are not looking for one—are counted as "not in the labor force". Many who are not in the labor force are going to school or are retired. Family responsibilities keep others out of the labor force. "Discouraged workers" are a subset of those who are "not in the labor force".
