The basic labor force data do not include data on earnings. Therefore, for the 60's, we require questions both from the basic labor force section of the survey, and from the March annual demographic survey. Second, we need to measure the number of people within each of these cells at the beginning and end of the period under study. From 1963-67, the CPS uses a 2 digit code which does not fully map into the categories we used for the later expansions, therefore the occupation codes for the 60's are essentially a different scheme. There are 32 codes for current occupation but only 21 codes for last year's occupation.
Sector is more manageable.
In the 60's it was possible generate a 21-category sector variable. Each household in the sample is interviewed for four consecutive months, then not interviewed for eight months, followed by four more consecutive months of interviews. Part of the sample changes every month so the sample is composed of households at various stages along their interview course in a given calendar month. Responding to the great social science interest in earnings, every year the CPS prepares a file containing the combined outgoing rotation interviews over the whole year. The file contains the labor force and employment series, the earnings and hours worked variables, and some basic demographic characteristics for about 30,000 individuals per month for 12 months.