Measuring Income and Wealth at the Top Using Administrative and Survey Data

Administrative tax data indicate that U.S. top income and wealth shares are substantial and increasing rapidly (Piketty and Saez 2003, Saez and Zucman 2014). A key reason for using administrative data to measure top shares is to overcome the under-representation of families at the very top that plagues most household surveys. However, using tax records alone restricts the unit of analysis for measuring economic resources, limits the concepts of income and wealth being measured, and imposes a rigid correlation between income and wealth. The Survey of Consumer Finances (SCF) solves the under-representation problem by combining administrative and survey data (Bricker et al, 2014). Administrative records are used to select the SCF sample and verify that high-end families are appropriately represented, and the survey is designed to measure comprehensive concepts of income and wealth at the family level. The SCF shows high and rising top income and wealth shares, as in the administrative tax data. However, unadjusted, the levels and growth based on administrative tax data alone appear to be substantially larger. By constraining the SCF to be conceptually comparable, we reconcile the differences, and show the extent to which restrictions and rigidities needed to estimate top income and wealth shares in the administrative data bias up levels and growth rates.