The CPS sample is a probability sample designed primarily to produce national and state estimates of labor force characteristics of the civilian non-institutional population 16 years of age and older. However, the CPS does not only sample the civilian non-institutional population 16 years of age and older; this is just the population used to calculate labor force statistics. The CPS samples households. Most CPS samples include demographic, family interrelationship, and other basic information on all members of sampled households, regardless of their age. Children are not included in the CPS until 1968 and not consistently included in the monthly data until 1982.
Questions related to employment (including those on income, employment status, labor force participation, occupation, industry, hours worked, etc.) are only asked of members of sampled households considered to be “adults” by the Census Bureau. The age threshold used to define “adult” has changed over time. This is reflected in the universes of employment-related variables. The universe of a variable describes who the variable is available for—in other words, who is asked the corresponding survey question. While children are not asked survey questions related to employment, they are still part of the CPS. To determine what the universe is for a given IPUMS CPS variable, after clicking on the variable name in the extract system, click the universe tab. For example, the universe of EMPSTAT was persons age 14+ in samples from 1962-1988, and persons age 15+ in samples from 1989 onward.