For present purposes, therefore, we will restrict the analysis to employees. We will also, for most of the analysis, restrict our attention to full-time employment, defined as working 35 hours a week or more. No useable CPS data is currently available before 1962, so our analysis must begin after the 1961 start date of the expansion. For example, employment level estimates in some years are appreciably higher or lower than those reported by other sources. The 1962 data is particularly problematic, therefore we decided not to use that year.
Later years become progressively better.
We decided to begin the analysis in 1963 as a compromise between the quality of the data and our need to include as many years of the economic expansion as possible. We did run the analysis using different years as our starting point, and the broad patterns of our conclusions were maintained. There are a number of changes in the data over the years that affect our methodological strategy and coding regimes. In particular, the sampling structure of the CPS dataset we use changes from the 1960s to the 1990s, and a number of the central survey questions used to define the variables of our analysis change in the two periods as well. For the 60's analysis, we use the annual CPS demographic data , collected in March of each year.