“Four-day week boosts revenue 8%.” “Revenue up by a third.” Revenue is the number that travels furthest from four-day week research and means the least without its footnotes. This is not cynicism; it is arithmetic. Read properly, the revenue evidence is genuinely reassuring. Read as headlines, it will mislead your board.
Here is the five-minute method we teach clients for any revenue claim, worked through the famous cases.
Question one: revenue for whom?
Pilot revenue figures are rarely whole-cohort. In the UK 2022 pilot, the widely quoted revenue rise — up 1.4% across the trial window — came from the subset of firms that reported comparable figures, not all 61 organisations. The US and Ireland pilots’ 8.1% rise during the trial window and South Africa’s 10.5% weighted average rest on participating firms that supplied numbers, in pilots firms chose to join. Averages over volunteers who report their revenue are a reasonable sign of “no collapse among engaged firms.” They are not an estimate of what your firm will bank.
Always ask: how many firms reported, out of how many in the pilot? If the headline cannot tell you, demote it.
Question two: compared with what window?
The UK pilot also carried a “+35%” style comparison against a similar earlier period, a figure that plainly bundles firm growth, survivorship and a favourable comparison window alongside any hours effect. Growing firms join pilots; pilots run for six months; revenue in growing firms grows. Window choice can manufacture most of a headline, which is why the honest sentence from the same data is the modest one: revenue was broadly stable to slightly up during the trial, in firms motivated to make it work. Germany’s 2024 pilot, with a more controlled design, reported broadly stable revenue and profit — less exciting, more believable, and arguably the most useful number in the field.
Compare like with like: the same months a year earlier for seasonal businesses, and ideally a business that did not change its hours. Very few pilots offer the second. Say so.
Question three: is it revenue per what?
Total revenue can rise while hours quietly rise too — the finding that should most worry a reader. Divide by actual hours worked. If revenue held while genuine hours fell a tenth, revenue per hour rose; that is a real and interesting result. If revenue held because Friday work went underground, you have measured concealment. This is why serious scorecards put timesheets, overtime and after-hours activity next to the money. A revenue claim unaccompanied by an hours claim is only half a sentence.
Question four: how big is the base?
Revenue percentages from pilots dominated by small firms ride on small, volatile bases. One contract landed or lost can swing a 20-person firm’s half-year by double digits. The same caution the UK researchers attached to their leaving and sick-day percentages — large relative moves on small bases — applies with equal force to money. Ask for the count of firms, the spread (not just the mean), and how many firms went down. A pilot where most firms were flat, a few rose and a few fell is informative. A single average hides all of that.
What to say in your own boardroom
Use the sentence the evidence supports: “In every major pilot to date, revenue has been broadly maintained in firms that redesigned work — typically stable, sometimes modestly up during the trial window, measured over subsets of volunteering firms.” That sentence will survive a hostile question. “Revenue rises 8%” will not, and the afternoon it collapses it will take the wellbeing evidence — which is much stronger — down with it.
The four-day week does not need revenue miracles. Output held, people recovered, fewer resigned: that is already a business case. Keep the money claims modest, and they will stay true.
Sources
- UK four-day week pilot revenue and continuation results — Autonomy, University of Cambridge, Boston College and 4 Day Week Global, February 2023.
- US and Ireland pilot revenue results — 4 Day Week Global and Boston College researchers, December 2022.
- Germany four-day week pilot revenue and productivity findings — University of Münster and Intraprenör, October 2024.
- South Africa four-day week pilot results — 4 Day Week Global, Boston College and Stellenbosch University, 2023.
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