Staff forgive a rough first month of a four-day week. They do not forgive discovering in December that holiday was miscounted, a bonus target assumed five days, or a public holiday on their day off simply vanished.
The model is simple — 100-80-100: full pay, 80% of the time, a commitment to full output. The contract language underneath decides whether the pilot builds trust or spends it. This post covers the clauses to settle before launch: pay basis, leave, public holidays, bonuses, pensions and promotion.
Start with the pay basis, in one sentence
State it explicitly. The researched basis is: salary unchanged; scheduled hours reduce from 40 to 32; salary is for the role and its outputs, not a count of hours. Iceland’s trials (2015–2019, over 2,500 public workers), the UK 2022 pilot and the US and Ireland pilots all held pay — telling staff the day off is no loan against future reviews, and payroll not to pro-rate by default.
Alternatives are different products. A pro-rata pay cut is a part-time arrangement, not the pilot model. If any element is conditional — continuation linked to service levels, say — disclose the condition and its measure. Some UK variants used conditional designs; they can work, but undisclosed conditions read as a trap.
For hourly-paid staff, state the hourly outcome directly: as full-time effective hourly value rises, part-time rates normally need the same pro-rata uplift to avoid a two-tier workforce. Price it into the pilot budget rather than discovering it in month three.
Leave: count in hours, publish the holiday rule
“Days” of leave stop meaning one thing when schedules vary — eight hours for one colleague, ten for a compressed pattern, zero for the person whose day off it is. Convert balances and accrual to hours before the pilot, show each person their balance in hours, and let them book in hours.
Then decide the public-holiday rule, because every calendar produces it within weeks. If a holiday falls on a scheduled day off, three treatments are common: credit the hours back to take later; no credit (the holiday is a non-working day for all, and rota luck evens out); or pool and rotate days off so collisions distribute fairly. Any can be defended; silence cannot. Pick one, publish two worked examples in the FAQ, and apply it consistently.
Atom Bank made a 34-hour week permanent in December 2022 (applications up about a third, departures down about a fifth) after spelling out these operating rules in practice, not just principle.
Bonuses, pensions and the quiet clauses
Bonuses and targets. Sales, utilisation and throughput targets set on five-day assumptions quietly demand five days of work. Re-base every target to the new schedule and show the working. If the bonus pool depends on company results, confirm pilot-period results count normally; excluding them teaches staff the pilot is not real business.
Pensions and benefits. Check hours-based eligibility for pension enrolment, health coverage and insured benefits so nobody crosses a threshold by accident, and confirm in writing that percentage-of-salary pension contributions are unaffected.
Overtime and peak weeks. Decide now: can the day off be worked exceptionally, at what rate, with whose approval, repaid how? “Flex informally” becomes weekly flexing, and pilot data will describe a five-day week.
Promotion and performance. Commit to comparing ratings, promotions, reviews and acting-up opportunities across day-off patterns. Perpetual Guardian’s monitored 2018 trial tracked leadership and commitment alongside output; measure standing and progression, not just tasks, and learn of any pattern penalty during the pilot, not after permanence.
Write trial terms that can end well
A credible trial document fits on two pages: the model and who it covers (including part-time treatment); patterns and day-off allocation; pay basis, hourly treatment, bonus rebasing, pension confirmation; leave in hours and the holiday rule with examples; timekeeping and the day-off work rule; customer and quality floors and how they are measured; review date, decision criteria, and the notice and process if the pattern is adjusted or reverted.
The UK pilot’s firms pre-committed to a genuine trial with an end point — 92% were continuing at the initial report — and people accept a “no” judged against agreed criteria. What destroys trust is drift followed by rumour.
Actionable steps
- Convert leave to hours this month, before any announcement, and reconcile each balance with its owner.
- Pick the public-holiday rule and publish two worked examples covering fixed and staggered days off.
- Re-base every target — sales, utilisation, bonus, throughput — keeping old and new bases visible for one cycle.
- Get written confirmation from payroll and benefits providers that thresholds, contributions and insured benefits are unchanged at 32 hours.
- Add a progression audit to the scorecard: ratings and promotions cut by day-off pattern and contract type.
- Sign the two-page trial terms with a review date staff can put in their diaries.
In a four-day week the contract language is not paperwork after the change. It is the change, in a form staff can rely on when the rota tightens.
Sources
- Iceland trials 2015–2019 — Autonomy / Alda, July 2021: https://phys.org/news/2021-07-shorter-week-boost-productivity-burnout.html
- UK 2022 pilot — Autonomy / Cambridge / Boston College, 21 February 2023: https://www.sciencedaily.com/releases/2023/02/230221113132.htm
- US and Ireland pilots 2022 — 4 Day Week Global, December 2022: https://www.internationalworkplace.com/community-zone/news/four-day-week-pioneering-pilot-program-a-huge-success-new-research-reveals
- Atom Bank, 21 December 2022: https://www.personneltoday.com/hr/atom-bank-four-day-week/
- Perpetual Guardian, New Zealand, 2018: https://www.sciencealert.com/this-4-day-work-week-experiment-went-so-well-company-keeping-it-perpetual-guardian-engagement-balance
Day5Group is a consultancy that assists in the transition to a 4 day work week. More about Day5Group · All blog articles