Each country participating in IALS agreed to design a high-quality probability sample representing the adult non-institutional civilian population aged 16 to 65. In the United States, respondents were selected from a sample of individuals in housing units who were completing their final round of interviews in the Current Population Survey (CPS).
The CPS is a large-scale, continuous household survey of the non-institutional civilian population, aged 15 and older, conducted by the Bureau of Labor Statistics. The CPS sample is selected using a stratified multi-stage design. Housing units in the CPS sample used for IALS were derived from the 1980 Census and from lists of new construction, when available.
The IALS sample was limited to 60 of the CPS's 729 primary sampling units (PSUs). Within these 60 PSUs, participants were selected using a proportional probability sampling procedure. The final sample size for the United States was 3,053. For more information the sample design of IALS, please see the NCES IALS Technical Report.