A large majority of British companies that took part in a 2022 pilot program to test the idea of a four-day, 32-hour work week are still maintaining that schedule, researchers found.

Fifty-four of the 61 companies that took part in the six-month trial have continued with the shortened week, with 31 of them saying that this is a permanent decision, according to a report issued this month.

The pilot was organized by advocacy group 4 Day Week Global in collaboration with the research group Autonomy, and researchers at Boston College and the University of Cambridge.

Among the findings were that employees reported a range of benefits related to their sleep, stress levels, personal lives and mental health, while resignations decreased. Companies reported “broadly the same revenue” during the course of the trial, according to The Washington Post, but their revenues rose by 35 percent on average when compared with a similar period from previous years.

"It's hard to overstate how good it's been," one of the participants told Business Insider after the trial's end. "It's honestly changed my life. … I would say it's changed my attitude toward how I work."

One hundred percent of managers and CEOs consulted for the follow-up study said that the four-day week had a positive or very positive impact on their organization. When asked what the shorter working week had changed, 82 percent of surveyed companies reported positive impacts on staff well-being. 50 percent saw positive effects on reducing staff turnover, and 32 percent said the policy had noticeably improved their recruitment.

A separate follow-up survey with staff from 47 of the original pilot organizations also showed a maintenance in the improvements in physical and mental health, work-life balance and general life satisfaction, as well as reductions in burnout, found at the end of the original pilot.

The pilot program attracted the attention of an American lawmaker. In March 2023, Rep. Mark Takano (D-Calif.) reintroduced his 2021 bill to amend the Fair Labor Standards Act of 1938 to reduce the standard workweek from 40 hours to 32 hours.

But some British employers have found that they encounter challenges when managing a four-day week, The Financial Times (FT) reported.

The CEO of a participating company in the trial, digital marketing agency Trio Media, noticed a decline in “staff effort” after making the four-day week permanent. “It highlighted to me we needed to work at [productivity],” Clare Daniels told the FT.

Gary Conroy, chief executive and founder of 5 Squirrels, a skincare producer that also participated in the trial, came to a similar conclusion. “The discipline always needs to be maintained,” he told the FT. “Every single person slips at some point and the productivity will slip.”

Since the trial, some companies have varied their working hours. Some have a universal day off, typically a Friday, while others have allowed teams to decide their day off. Seven percent of the companies in the trial opted for a 4.5-day week.

Trio Media calls the fifth day an “on-call day.” “If there is a business requirement, people work five days,” said Daniels. “We need the flexibility both ways.”

Michael Sanders, a professor of public policy at King's College London, told the FT that it was hard to draw broad conclusions from the trial. “The study is a self-selecting group of employers and, within them, a self-selecting group of employees,” he said. “There’s no effort to identify the counterfactual—what would have happened otherwise.”

Gemma Dale, a consultant and lecturer at Liverpool Business School, also noted the limitations of the trial. More than three-quarters of respondents had fewer than 50 employees, and only 7 per cent had more than 200 staff, making her skeptical of how transferable the participants’ findings were.

The new report found that work intensity rose during the trial, but fell a year later. But the efficiency drive prompted some staff to leave 5 Squirrels. “They like a more social element to work,” Conroy told the FT, and “would rather be there longer and have longer lunches; they miss the chats.”

Conroy said that most of the time saving was achieved by working smarter. “People are challenging the processes, coming up with hacks ... using more tech; the sales and marketing people are using AI, meeting minutes are using AI.”

Daryl Hine, chief operating officer at financial services firm Stellar Asset Management, agreed that technology is key to managing a shortened work week. “We couldn’t implement a four-day week if we didn’t invest in tech at the same time,” he told the FT.