Polynomial Analysis of U.S. Real Wage using U.S. CPI and Weekly Earnings Data

Yuhong Dai; Chenyi Hu; Zixuan Li

doi:10.54097/4vdr2x51

Authors

Yuhong Dai Hefei Thomas School, Hefei, China
Chenyi Hu Shanghai World Foreign Language Academy, Shanghai, China
Zixuan Li Nanjing Xianlin Foreign Language School, Nanjing, China

DOI:

https://doi.org/10.54097/4vdr2x51

Keywords:

Polynomial analysis; Wage analysis; CPI.

Abstract

The United States has been concerned with inflation ever since early 2019. Inflation is a rise in prices that reduces purchasing power. When the nominal wage growth fails to keep up with price growth, it weakens the real purchasing power and puts pressure on the living standards of households. This paper utilized official data from the U.S. Bureau of Labor Statistics, including monthly CPI-U figures and quarterly median weekly income statistics. Two quantitative techniques were used: an exact sequence model for measuring cumulative inflation and purchasing power loss, and a polynomial least squares fit to measure the shape of price and wage movements over time. The results indicate that the cumulative CPI-U inflation is about 26.1% from December 2019 through December 2025, increasing to about 27.2% in February 2026. During that same time, nominal weekly earnings increased meaningfully, while real weekly earnings only increased marginally and fell during the inflation spike.

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