Prime-Age Adult Working Hours in US Remain Stable at 30 Per Week for Over a Century, Global Study Finds

New research by Amory Gethin and Emmanuel Saez reveals a remarkable long-term stability in working hours for prime-age adults globally, with a striking example from the United States. The study, titled "Global Working Hours," indicates that despite significant economic development over the past century, the average weekly hours for this demographic have remained largely unchanged. As researcher Amory Gethin highlighted, "> hours among prime-age adults are stable with development. This is particularly visible in long time series. For instance, prime-age hours were about 30 per week in the United States in 1900, and still are exactly 30 per week today."

The comprehensive paper, published as NBER Working Paper 34217 in September 2025, utilizes labor force surveys from 160 countries, encompassing 97% of the world's population. It also constructs time series data spanning over 20 years in 86 countries, providing an unprecedented global perspective on labor trends. This extensive dataset allowed the economists to observe nuanced patterns in working hours across different demographic groups and stages of economic development.

A key finding of the research is that the stability in prime-age working hours often masks significant underlying shifts in gender-specific labor patterns. While hours worked by prime-age men in middle-to-higher income countries have seen a decline, this reduction has been quantitatively offset by a rise in female labor force participation. These opposing dynamics for men and women have largely compensated each other, contributing to the observed overall stability in prime-age adult working hours.

Beyond prime-age adults, the study also identifies distinct trends for other age demographics. Hours worked by young adults (15-19) and the elderly (60+) tend to decrease with economic development, primarily driven by increased school attendance and the expansion of public pension coverage, respectively. The researchers also noted a strong negative correlation between labor taxes and prime-age hours worked, suggesting that public policies and regulations play a substantial role in shaping labor market outcomes.