The annual IRS cross-sections are stratified samples, with the probability of inclusion rising steeply with total income. 6 Variables includemost of the values from the 1040 tax form and associated schedules, as well as data from Social Security records, such as the age and gender of each individual represented on the return. 7 The 1987 cross-sectional sample of about 88,000 returns is the base year of the panel. The panel was constructed by matching, in each subsequent year, the full population of tax returns that appeared in the 1987 sample. This method allows individuals to be tracked over time regardless of income changes and changes in marital status. 8 We exclude.
