The Biggest Trial Yet Confirms Four-Day Workweek Makes Employees Happier
The largest yet study on a four-day workweek included 141 companies, 90 percent of which retained the arrangement at the end of the six-month experiment
Moving to a four-day work week without losing pay leaves employees happier, healthier and higher-performing, according to the largest study of such an intervention so far, encompassing six countries. The research showed that a six-month trial of working four days a week reduced burnout, increased job satisfaction and improved mental and physical health.
The study’s authors had wondered whether a condensed working week would add to employees’ stress. “When workers want to deliver the same productivity, they might work very rapidly to get the job done, and their well-being might actually worsen,” says lead author Wen Fan, a sociologist at Boston College in Massachusetts. “But that’s not what we found.” Instead, staff members’ stress levels fell.
The study was published July 21 in Nature Human Behaviour.
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Pandemic upheaval
Levels of employee stress and burnout soared during the COVID-19 pandemic, leading many workers to quit their jobs, the authors note. The result was large numbers of unfilled positions in some labour markets.
To see whether shorter weeks might be the antidote for poor morale, researchers launched a study of 2,896 individuals at 141 companies in Australia, New Zealand, the United States, Canada, Ireland and the United Kingdom.
Before making the shift to reduced hours, each company that opted into the overhaul was given roughly eight weeks to restructure its workflow to maintain productivity at 80% of previous workforce hours, purging time-wasting activities such as unnecessary meetings. Two weeks before the trial started, each employee answered a series of questions to evaluate their well-being, including, “Does your work frustrate you?” and “How would you rate your mental health?” After six months on the new schedule, they revisited the same questions.
Overall, workers felt more satisfied with their job performance and reported better mental health after six months of a shortened work week than before it.
Winners and losers?
A common criticism of the four-day work week is that employees can’t produce the same output in four days as in five. The study didn’t analyse company-wide productivity, but it offers an explanation for how workers can be more efficient over fewer hours. “When people are more well rested, they make fewer mistakes and work more intensely,” says Pedro Gomes, an economist at Birkbeck University of London. But Gomes would like to see more analysis of the impacts on productivity.
Fan notes that more than 90% of companies decided to keep the four-day work week after the trial, indicating that they weren’t worried about a drop in profits.
The authors also looked at whether the positive impacts of shorter work weeks would wane once the system lost its novelty. They collected data after workers had spent 12 months after the start of the trial and found that well-being stayed high.
But because companies signed up for the trial voluntarily, the results might overestimate the true effect of the four-day work week across a range of companies. And because all outcomes were self-reported, employees might have exaggerated the benefits in the hope of keeping their extra day off. The authors call for randomized studies to test the scheme.
This article is reproduced with permission and was first published on July 21, 2025.
