A half-year trial testing the benefits of a four-day workweek just kicked off in the United Kingdom, with 3,300 employees at 70 companies, from financial services to fast-casual restaurants tracking their experiences with an altered workweek.

The pilot comes as the return-to-office push continues to perplex many employers, and downtown business districts lament the lack of foot traffic or the full-time return of daily commuters.

The biggest such trial ever conducted, this UK test will provide workers with 100% of their pay for 80% of their normal hours, and measure if such a setup provides a better quality of life and increases productivity.

Set to run from June through November, the trial will track changes in productivity and employee well-being, data that will then be studied by researchers at Cambridge University, Boston College and Oxford University.

Nonprofits 4 Day Week Global and the 4 Day Week Campaign, as well as Autonomy, a UK think tank, organized the experiment. The start of the pilot was pushed back to the week of June 6 due to the Queen’s Jubilee.

According to new survey data from Gartner, which consulted with 220 primarily North America-based human resources leaders in late June, 16% of companies surveyed have considered moving to a four-day workweek, with 5% actually implementing the change.

A similar series of trials that took place in Iceland featuring 2,500 workers was considered an “overwhelming success” by researchers from Autonomy and the research group ALDA, the Association for Sustainable Democracy.

A BBC report noted that in the aftermath of the trials, Icelandic unions renegotiated working patterns and now 86% of Iceland's workforce either has moved to a schedule featuring the same pay for shorter hours, or it will gain the right to make such a switch.

Similar experiments are being conducted in Spain and New Zealand, and advocates have argued the move also has significant environmental benefits. Writer and journalist Anne Helen Petersen, who wrote a detailed newsletter about the four-day workweek, found that companies across the globe have found shorter workweeks result in better employee satisfaction, more productivity and vast savings for the employer.