The world’s largest four-day working week trial has been “a resounding success” according to findings published this month. The trial, comprising 61 companies and around 2,900 workers, took place in the UK from June to December 2022 and the results show that of the 61 companies that participated, 56 are continuing with the four-day week (92%), with 18 confirming the policy is a permanent change.

Companies taking part, which included a range of organisations from diverse sectors and sizes, were not required to rigidly deploy one particular type of working time reduction or four-day week, so long as pay was maintained at 100% and employees had a ‘meaningful’ reduction in work time.

Resisting the idea that the four-day week must be ‘one-size-fits-all’, each company designed a policy tailored to its particular industry, organisational challenges, departmental structures and work culture. A range of four-day weeks were therefore developed, from classic ‘Friday off’ models, to ‘staggered’, ‘decentralised’, ‘annualised’ and ‘conditional’ structures.

The report results draw on administrative data from companies, survey data from employees, alongside a range of interviews conducted over the pilot period, providing measurement points at the beginning, middle and end of the trial.

Some of the most extensive benefits of shorter working hours were found in employees’ wellbeing. ‘Before and after’ data shows that 39% of employees were less stressed, and 71% had reduced levels of burnout at the end of the trial. Likewise, levels of anxiety, fatigue and sleep issues decreased, while mental and physical health both improved.

Measures of work-life balance also improved across the trial period. Employees also found it easier to balance their work with both family and social commitments – for 54%, it was easier to balance work with household jobs – and employees were also more satisfied with their household finances, relationships and how their time was being managed.

60% of employees found an increased ability to combine paid work with care responsibilities, and 62% reported it easier to combine work with social life.

However, other key business metrics also showed signs of positive effects from shorter working hours. Companies’ revenue, for instance, stayed broadly the same over the trial period, rising by 1.4% on average, weighted by company size, across respondent organisations. When compared to a similar period from previous years, organisations reported revenue increases of 35% on average – which indicates healthy growth during this period of working time reduction.

The number of staff leaving participating companies decreased significantly, dropping by 57% over the trial period. For many, the positive effects of a four-day week were worth more than their weight in money. Fifteen per cent of employees said that no amount of money would induce them to accept a five-day schedule over the four-day week to which they were now accustomed.

Charlotte Lockhart, 4 Day Week Global Co-Founder and Managing Director, said:

“We’re delighted to add these overwhelmingly positive results to our ever-growing evidence base in favour of reduced-hour, output-focused working. Not only do these findings demonstrate that the UK pilot programme was a resounding success, but it is encouraging to note that they largely mirror the outcomes from our earlier trials in Ireland and the US, further strengthening the arguments for a four-day week.

“While the impacts on business performance and worker wellbeing are expected and welcome, it’s particularly interesting to observe the diversity in findings across various industries. These results, combined with our previous research demonstrate that non-profit and professional service employees had a larger increase in time spent exercising, while the small group of construction/manufacturing workers had the biggest reduction in burnout and sleep problems. Certainly something to explore further in future pilots.”

Dr David Frayne, Research Associate at University of Cambridge, said:

“The method of this pilot allowed our researchers to go beyond surveys and look in detail at how the companies were making things work on the ground. We feel really encouraged by the results, which showed the many ways companies were turning the four-day week from a dream into a realistic policy, with multiple benefits. We think there is a lot here that ought to motivate other companies and industries to give it a try.”

In another trial, a findings report outlines how South Cambridgeshire District Council’s four-day week trial has seen £434,000 less spent on agency staff covering hard to fill roles.

The four-day week enabled the Council to fill ten permanent roles that it previously struggled to recruit to - particularly in the Planning Service, where the private sector pays more. This has led to the reduction in spending because directly employing staff in permanent roles is much more cost effective than hiring agency staff that the Council was relying on.

Under a four-day week, officers are expected to carry out 100% of their work, in 80% of the time, for 100% of the pay. The Council’s opening hours have been maintained so that they have been at least what they were before the trial – and have been extended on Wednesdays. There is evidence elsewhere that working a four-day week means people got more done in less time.

The four-day week trial for desk-based staff began in January 2023, to help attract and keep talented colleagues in an incredibly competitive local employment market. This includes staff at Greater Cambridge Shared Planning, a service shared with Cambridge City Council.

The Bennett Institute for Public Policy at the University of Cambridge independently reviewed the Council’s data from the initial three-month trial. They looked at data from 18 different key areas, covering performance in Planning, Housing, Transformation, Human Resources and Corporate Services and Finance.

The data showed that nine out of the 16 areas monitored show substantial improvement when comparing the trial period from January to March to the same period in 2022. The remaining seven areas monitored either remain at similar levels compared to the same period last year or saw a slight decline. The Bennett Institute noted however that not a single area of performance fell to a concerning level during the trial.

The report, set to be discussed by South Cambridgeshire District and Cambridge City Councillors in the weeks ahead, shows how it has cost £434,000 less employing colleagues permanently, rather than using agency workers, to cover 10 posts that could not previously be filled. This covers the period from when the trial was announced to the end of 2023.

In addition to the ten roles that have been recruited to permanently, the Council identified further posts that were being covered by agency staff at the start of the trial. Two of those posts have been deleted, and as part of the Council’s continued Transformation work – which is expected to deliver additional savings of £2 million – a further ten roles have been absorbed into other roles or are externally funded.

There are also savings expected to be realised through reduced sickness absence due to the health and wellbeing benefits to staff from the four-day week. These benefits are expected to be most significant in roles that are more physical – such as amongst waste crews where musculoskeletal injuries can be more commonplace than in desk-based roles. A reduced overall fuel cost for Greater Cambridge Shared Waste, owing to the route re-optimisation programme and four-day week collection pattern, is also anticipated to deliver savings to the councils.

South Cambridgeshire District Council’s Lead Cabinet Member for Resources, Cllr John Williams, said:

“Our four-day week trial is about improving the consistency of services to residents and businesses – by helping us attract and keep hold of talented staff in a hugely competitive job market. We know we cannot compete on salary alone and so must find new ways of tackling our recruitment and retention issues… Importantly, we’ve spent £434,000 less on using agency staff to cover 10 roles we classed as hard to fill before the trial. This is because, since announcing the trial, we have been able to fill these roles permanently – rather than using agency workers to cover.”

Cllr Mike Davey, Leader of Cambridge City Council, said:

“The key thing for us is working out what’s best for our residents. So far during the trial we’ve seen high standards maintained in the services we share – planning and waste – with a five-day service maintained.”