What were the findings of the UK 4-day working week trial?

In 2022, 61 UK companies took part in the world’s largest four-day working week trial. Here’s what they learned – and advice on how you could try it yourself.

Abbi Melville • 
How to implement your own 4-day working week trial

Between June and December last year, 61 UK companies containing over 2,900 workers participated in the world’s largest four-day working week trial.

It was an attempt to answer the controversial question of whether employees working a 4-day week would be more productive than those working 5 days.

In this trial, employees were dropping to a 4-day week, but they would continue with the same workload as if working 5 days and therefore continue to receive 100% pay, not pro-rated pay.

This is known as the 100:80:100 4 day work week model: 100 percent of the pay for 80 percent of the time, in exchange for a commitment to maintaining at least 100 percent productivity.

This experiment would put the 4-day week increased productivity hypothesis to the test, and potentially to bed, if the results were disastrous!

But, thankfully for 4-day-week advocates and for most of the participants the experiment was a resounding success, at least according to the team who were behind the study.

92% of participants retained the four-day week after the study finished

Within the confines of the study, the results do seem to back up their conclusion of resounding success with 56 out of 61 companies (92%) who participated in the study choosing to continue with the study.

Some of the key employee benefits in the study were:

  • 39% of employees were less stressed.
  • 71% had reduced levels of burnout.
  • 54% found it was easier to balance work with household jobs.
  • 60% of employees found an increased ability to combine paid work with care responsibilities.
  • Staff turnover dropped by 57%
  • 62% reported it easier to combine work with social life.

Revenues increased marginally

Also, company revenues stayed broadly the same over the trial period, rising by 1.4% on average with organisations reporting revenue increases of 35% on average.

However, with only 18 out of 61 (32%) choosing to make this a permanent change we have to be careful about what conclusions can be drawn from the study.

Clearly, most of the participants aren’t sure enough about the results to commit to this long-term. This is kind of understandable given the relatively short duration of the study. 6 months was probably not long enough to convince them that a permanent, structural increase in working efficiency had been achieved. They needed longer to rule out the honeymoon effect.

So, while the study was a success there has been an appropriately conservative forward-looking approach.

Predating the UK is Iceland’s successful 100:80:100 four-day week trial which took place between 2015 and 2019. And while the 4-day week is now prevalent in Iceland, they have had 9 careful years to embed it.

We are seeing this willing but cautious approach to the 100:80:100 4-day working week, being replicated in other countries, which further underlines the initial promise of this UK pilot study.

Portugal is one of the most recent countries to announce a trial of a 100:80:100 four-day week in June 2023. As a result of the successful trials, the four-day working week is gathering momentum: Wales is currently debating a four-day working week trial, and Scotland is going to be trialing a 4-day working week too.

How to implement your own 4-day working week trial

If HR managers or people managers reading this are considering a 100:80:100 four-day week trial, how could you go about it? Here are three best practices we derived from the research document.

1.  Prep the team

The work trial research report showed that implementation wasn’t an overnight thing and participating companies typically required 2 months of preparation. This involved workshops, coaching, mentoring, developing HR metrics, and incorporating these into HR software systems so performance could be monitored.

2.  Flexibility of approach

Apart from following the 100:80:100 principle, you don’t need to be confined to a one-size-fits-all approach: participants followed a range of 4-day models, including classic, ‘Friday off’ models and ‘annualised structures.

3.  HR data-driven approach

There’s too much at stake for this to be built on guesswork, the 100:80:100 4-day working week pilot was driven by HR metrics, and, given the volume and complexity of the incumbent’s data points it would need to be implemented using HR software.

In general, the work trial was a resounding success, but it’s clear that it does not work for all. However, given the likely benefits to employee well-being, engagement, and productivity, it could be a great way for your business to gain a competitive edge.