The most reasonable objection to any four-day-week pilot result is also the simplest: of course people feel better in month three — it is new, it is exciting, and everyone knows they are being studied. Wait a year, the sceptic says, and the novelty will wear off.
The UK 2022 pilot is valuable precisely because researchers went back and checked. A year after the trial, the novelty explanation had a problem: most firms had not gone back.
What the follow-up found
The original UK pilot ran from June to December 2022 with 61 organisations and around 2,900 staff, on a 20 percent time reduction with no cut in pay. At the end of the trial, 92 percent of firms said they would continue, and 18 had already made the change permanent.
When Autonomy re-contacted the cohort a year later, 54 of the 61 organisations — 89 percent — were still operating a reduced working week. Thirty-one firms, just over half, had made it permanent. The wellbeing gains reported during the trial were described as maintained rather than faded.
That is not proof that every firm will thrive on four days forever. It is, however, the wrong shape for a novelty effect. Novelty effects decay. Firms do not usually keep an expensive, operationally demanding change for a year, convert it into contracts, and report the same wellbeing benefits because the excitement has not worn off yet.
Why durability is the more interesting number
Continuation is a harder test than satisfaction. During a pilot, continuing costs little: the end date provides cover, and nobody has yet had to renegotiate contracts, rebuild rotas or defend the change through a bad quarter. Making a reduced week permanent means doing all of that, in full knowledge of where it pinches.
So when roughly nine in ten firms are still operating the model a year on, something more than enthusiasm is doing the work. The firms themselves pointed to the mechanisms this blog returns to repeatedly: meetings cut and kept cut, processes redesigned rather than merely paused, recruitment and retention gains that finance directors could see, and staff who had reorganised their lives around the day and would treat its removal as a pay cut in kind.
The firms that drifted back are informative too. In this and other pilots, reversal tends to follow the same script — the calendar changed, the workload underneath it largely did not, and intensity filled the gap until the model became unsustainable. Durability, in other words, is not a property of the four-day week in the abstract. It is a property of whether the redesign underneath it was real.
The honest caveats
Three cautions belong in any fair reading. First, these were volunteer firms, disproportionately small and knowledge-based, led by people who wanted the change to work. Their results do not automatically transfer to a reluctant organisation or a 24/7 coverage service.
Second, most of the evidence is self-reported. Wellbeing and productivity measures in these pilots lean heavily on surveys; objective output-per-hour data across a whole cohort remains rare, and firms reporting results a year on are, inevitably, more likely to be the ones still in the scheme.
Third, a year is not a decade. Twelve-month follow-ups are encouraging and consistent with the wider research, but independent data beyond roughly two years is still thin. Organisations that make the change permanent should keep measuring — and should expect to publish a two-year and three-year picture, including wherever the model had to be adjusted.
What this means if you are deciding now
Treat the UK follow-up as evidence against the laziest objection, not as a guarantee. “It is just a novelty effect” no longer fits the best data we have: too many firms kept the change, at real administrative cost, for that to be the whole story.
The better question is the one the follow-up lets you ask. Of the firms still operating a reduced week a year later, what did they actually change — in meetings, workload, coverage and management — to make the day off survive contact with ordinary business? That is the transferable lesson, and it is why a pilot should be judged not only on how people feel in month three, but on whether the organisation is still running it, willingly, in month fifteen.
Sources
- Autonomy, UK 2022 pilot one-year follow-up, reported 26 Feb 2024 — https://www.hrdconnect.com/2024/02/26/one-year-on-uks-4-day-work-week-trial-has-been-a-success/
- Autonomy / University of Cambridge / Boston College, UK 2022 pilot results, reported 21 Feb 2023 — https://www.sciencedaily.com/releases/2023/02/230221113132.htm
- 4 Day Week Global, US and Ireland pilots, Dec 2022 — https://www.internationalworkplace.com/community-zone/news/four-day-week-pioneering-pilot-program-a-huge-success-new-research-reveals
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