Critics of shorter working week trials consistently miss the mark
Dr. Will Stronge, Prof. Brendan Burchell and Dr. David Frayne
21st July 2025
Introduction
A recent comment piece has sought to cast doubt on the validity of the four-day week trials conducted globally in recent years – focusing particularly on those that the Autonomy Institute have worked on or reported. While scrutiny is welcome and necessary in any evolving policy space, many of the arguments presented are based on outdated assumptions about how innovation should be trialled, measured, and evaluated. Below, we respond to the three central claims.
1. On ‘Randomised Control Trials’
Kauhanen’s main claim is that working time reduction pilots need to have control groups, ideally randomised ones. The first thing to say is that some high-profile pilots have indeed included control groups, such as the Portugal pilot, the German pilot, and one of the North American pilots, so he is plainly mistaken. These experiments all find no change in the control companies compared to well-being improvements in treatment organizations. His claim reflects a very narrow view of what constitutes rigorous evidence. Randomised controlled trials (RCTs) have their place (largely in laboratory settings), but they are by no means the only method for establishing rigorous causal relations. This is especially true when it comes to complex organisational interventions like a reduction in working time.
In real-world employment settings, there are numerous challenges. First, there is the issue of identifying what a suitably similar control group would even look like across diverse firms with different business models, workforce compositions, and sectoral dynamics. Let’s put the question back to the critic: who would the control group be exactly? Another, similar company? There are many variables that would make this invalid: different staff competency levels, different financial situations, different management styles, different staff backgrounds and ways of working – the list goes on. Could the control group be a different part of the same company? In this case you would run into a different set of issues, including the difficult workplace culture that could emerge because some staff are getting Fridays off and some are not, or the difficulty of isolating productivity between teams in many cases, or the risk of comparing staff who do different jobs. Having queried many people about this issue, no one, neither policymakers nor academics, nor heads of NGOs, have been able to offer us a compelling proposal for what an RCT would look like for this multifaceted policy. Instead, in many cases, we have considered the same organisation’s performance in a comparable, previous period of operations, as a baseline.
2. On measuring productivity and wellbeing
Kauhanen makes another claim that there are not well-defined measurements of productivity and wellbeing in report cases of shorter working week pilots. Again this is obviously not true. Wellbeing was a core dimension of our 2022 pilot design, as well in the Iceland experiment, and the data collected reflects this. Participants in the UK pilot answered a robust series of validated wellbeing questions, generating a significant body of evidence around stress, burnout, sleep, satisfaction, time use with friends and work-life balance. It’s a shame that Kauhanen didn’t take the time to read that section of the paper, or explore the raw data that can be downloaded from the website or read the rigorous well-being paper of our colleagues which is soon to be published in Nature Human Behaviour, and has been available online for more than two years.
There are various studies of biometric markers underway, e.g. by Charlotte Rae at Sussex University in the UK, although this can only tell us part of the picture. Endocrinologists will tell you (as they have told us in the past) that tracking something like cortisol levels to measure stress risks over-interpreting, mainly due to their sensitivity to factors beyond work. Qualitative interviews and structured surveys (which we carried out as part of the pilot) remain among the strongest tools for capturing lived experience.
When it comes to productivity measurements, Kauhanen is also mistaken: in the studies he refers to, there are plenty of productivity measurements mentioned. For instance, in the multi-year Iceland experiment, many of the statistics come from Reykjavík City’s own studies of the labour inputs and services outputs across the trial period. The Autonomy report picks out a number of these case studies, including, for example, increases in the number of invoices processed by the Department of Accountancy despite reduced working hours. Kauhanen would do well to go to the references list in that report and dive into the sources: he’ll find plenty of data to reckon with!
In the 2022 coordinated trial of 61 diverse firms, a universal metric of productivity was of course not feasible – nor appropriate, given diverse industries and ways of operating. Instead, we focused on key quantitative indicators (such as revenue and sickness data) that every firm could provide, while supplementing these with in-depth managerial interviews to understand changes in workflow, output quality, and operational efficiency. Beyond those noted studies, there are other recent examples where plenty of productivity data were gathered – see for example the 24 Key Performance Indicators in the trial within a local council in the UK here.
In our bespoke private engagements with organisations, more tailored productivity metrics are used to assess outcomes, because leaders rightly expect insights tied to their specific business goals. The trial structure was built to be scalable and adaptable, not one-size-fits-all. Autonomy have now worked with over 100 organizations of different scales – from Deloitte, to small charities – it would be remarkable if these organisations undertook such a significant shift in their operations and didn’t track how staff performed compared to prior data.
3. On the evidence base
Kauhanen’s final, perhaps most sensible point, is not in fact a criticism at all: he claims that research on four-day weeks is sparse and not definitive yet. While we disagree – there is a lot of existing research – we should all want more analysis and experimentation of this working practice, which is showing promising signs in diverse settings.
The research literature is rapidly growing, and the vast majority of the data points clearly in one direction: that a well-managed reduction in working hours can deliver benefits for both organisations and employees. That said, we do not claim universality. Every pilot is a live experiment – grounded in whether a shorter working week makes sense for that specific organisation.
The methodology at Autonomy embraces this. Regarding the pilots that Autonomy have been involved in, we let the organisations, their leaders and their staff demonstrate what works and what doesn’t. Kauhanen makes sarcastic comments about what he sees as our bias, but the bottom line is that one has to deliver for clients: a pilot really is an experimentation as to whether reduced hours is right for them, speaking to their organisational needs.
In this sense, the proof is in the practice: after successful trials, Autonomy keeps in touch with past clients to check-in on how the four-day week is going (see this report for example, which shows the longer term endurance of the policy). These accounts reveal not just successes but also challenges, adaptations, and learnings. In doing so, one can create a more honest and useful foundation for others considering the shift.
Critics are correct to ask hard questions – but they should also be asking the right ones. The four-day week is not based on orthodox assumptions or ideology – it is grounded in practice: in what companies are actually doing, learning, and how they are adapting. Misplaced methodological dogmatism risks missing this. We welcome deeper, more pluralistic forms of evaluation – but let’s not conflate ungrounded orthodoxy with insight.
Dr. Will Stronge is Chief Executive of the Autonomy Institute.
Prof. Brendan Burchell is Professor in the Social Sciences at the University of Cambridge.
Dr. David Frayne is Fellow at the University of Salford.