What the Iceland trial studied and why it matters
The Iceland 4 day work week study examined how reducing hours from five to four days per week, without pay cuts, affected productivity, wellbeing, and public services across hundreds of workplaces and thousands of workers. Conducted between 2015 and 2019, it remains one of the world’s largest real‑world experiments on shorter working time. This overview explains the design, outcomes, and limitations, drawing on publicly reported findings from Icelandic authorities and published evaluations to provide a durable reference on how the trial has shaped ongoing debates about work time reform.
Design and scope of the Iceland trial
The trial was jointly run by the Icelandic government, unions, and researchers, involving around 2,500 workers across public sector agencies, private companies, and municipal workplaces. Participating sites moved to a 35–36 hour working week while maintaining full pay. The study used a mixed‑methods approach, combining quantitative performance data with qualitative interviews to assess impacts. Coverage spanned multiple industries, including education, healthcare, social services, and offices, allowing findings to inform a wide range of work environments and organizational sizes.
Key findings on productivity and service delivery
Across most workplaces, productivity stayed the same or improved, with many organizations reporting more efficient meetings, reduced absenteeism, and better focus on core tasks. Workers used the extra time for rest, care, study, and community activities, which contributed to higher reported energy and engagement. Public services largely continued without disruption, and in some sectors waiting times and reported errors decreased. These patterns suggest that, for many salaried roles, reducing hours can maintain or even enhance output while improving wellbeing, although results varied by context and job requirements.
Productivity and operational metrics at a glance
| Metric | Reported outcome | Source context |
|---|---|---|
| Working hours | 35–36 hours per week | Trial design documents |
| Pay change | No reduction (full pay maintained) | Union and government agreements |
| Productivity | Maintained or improved at majority of sites | Trial reports and evaluations |
| Absenteeism | Decrease or stable in most workplaces | Public sector summaries |
| Worker wellbeing | Reported improvements in stress, fatigue, and work–life balance | Employee surveys and interviews |
| Service continuity | No major disruptions; some improvements in waiting times and error rates | Sector evaluations |
Reported challenges and limitations
Not all workplaces saw the same benefits; some managers needed to adjust workflows, and a minority of organizations reported initial disruptions or the need for additional hiring to cover tasks. Certain job roles, particularly those requiring constant presence or physically intensive work, were less suited to a reduced schedule without operational changes. The trial also faced methodological constraints, such as varying implementation details across sites and limited long‑term follow‑up beyond the initial trial period, which makes it difficult to generalize findings to all regions or sectors.
Policy impact and uptake after the trial
Following positive outcomes, Icelandic unions, municipal governments, and national agencies adopted shorter working time agreements more broadly, extending reductions to tens of thousands of workers. The results informed ongoing policy discussions across Europe and encouraged pilots in other countries, even though each context requires local adaptation. The Icelandic experience is often cited as evidence that structural changes to working time can be feasible, but it also highlights the importance of clear agreements, management practices, and sector‑specific adjustments.
What the evidence implies for other countries
The study demonstrates that moving to a 4 day week can be practical within public institutions and many private workplaces, provided there is strong collaboration between employers, unions, and workers. Gains in wellbeing and perceived productivity are common, yet outcomes depend on existing workflows, technology, and job design. Policymakers considering similar reforms should examine local labor structures, legal frameworks, and sectoral needs, and pilot changes where appropriate to adapt the model safely and effectively.
Limitations and ongoing considerations
Because the trial was largely conducted in a single country with particular labor market institutions, results may not automatically translate to other economies or to more rigid or informal settings. Long‑term studies remain limited, and changes in legislation, technology, or economic conditions can alter how shorter weeks function over time. Continued evaluation and transparent reporting are essential to assess evolving impacts on productivity, work quality, gender equality, and organizational health.