Finance and Economics Discussion Series (FEDS)
July 2025
Lost in Aggregation: Geographic Mismeasurement of Income and Spending
Sinem Hacioglu-Hoke, Leo Feler, and Jack Chylak
Abstract:
Using zip-code median income as a proxy for household income is common in economics but can mask heterogeneity and yield misleading conclusions. Using zip-code median income and self-reported household incomes from a representative panel of 150,000 U.S. households, we decompose average retail spending for 2018-2024. When using self-reported incomes, we observe substantial divergence in spending between low- and high-income households starting in mid-2021. When using zip-code aggregates as a proxy, this divergence disappears. Our findings indicate a 35 to 75 percent discrepancy between zip-code aggregates and self-reported incomes, highlighting the limitation of zip-code aggregates as a proxy for household incomes.
Keywords: Spending, Income, Heterogeneity, Zip-code Average Income
DOI: https://doi.org/10.17016/FEDS.2025.050
PDF: Full Paper
Related Materials: Accessible materials (.zip)
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