Do Salary History Bans Reduce Wage Inequality? Evidence from Staggered State Adoptions

Abstract

Do laws prohibiting employers from asking about salary history reduce wage inequality? Beginning in late 2017 with Oregon and Delaware (coded as 2018 in our analysis), sixteen US states have enacted private-sector salary history bans aimed at breaking cycles of wage discrimination. Using American Community Survey data from 2012-2023 and a staggered difference-in-differences design with the Callaway and Sant'Anna (2021) estimator, I examine whether these laws compress the wage distribution beyond their documented effects on the gender wage gap. Across all workers, salary history bans reduce the 90-10 log wage gap by approximately 0.05 log points (about 2-3 percent of the pre-treatment gap of 2.05), with effects concentrated among workers in high-wage-dispersion industries. Event study estimates show no evidence of differential pre-trends and effects that persist and grow over time. Robustness checks using alternative control groups, Sun and Abraham (2021) estimation, and placebo outcomes confirm the main findings. These results suggest that salary history bans have broader equalizing effects beyond their original gender equity motivation, with implications for labor market design and information disclosure policy.