About 3,300 workers at 70 companies in the U.K. entered a pilot program of the four-day work week starting Monday and ending in November.

The pilot program will give employees around 32 hours of work per week instead of 40, or four of the five typical work weekdays. Employees will still receive the same pay and are expected to maintain the same productivity levels. Companies taking part in the trial range from small "fish and chip" restaurants to large financial firms.

The group 4-Day Week Global is working with the U.K. think tank Autonomy for the pilot, along with researchers at Cambridge, Boston College, and Oxford University.

Previous pilot programs were held on a smaller scale in the U.S., Canada, Australia, Iceland, and New Zealand. CNN also reports that trials in Spain and Scotland will take place later this year.

A push for a four-day work week comes after the global COVID-19 pandemic, which changed the thinking around the traditional workplace culture and work-life balance. Many workers report preferring remote or hybrid work over the full-time, in-office demands of many companies.

Still, companies in the U.S. mandate employees return to the office despite the growing shift in preference. More recently, Tesla CEO Elon Musk sent a company email pushing employees to return to the office.

Juliet Schor, a professor of sociology at Boston College and lead researcher on the pilot, told The Guardian that the team will monitor progress throughout the program to look for any changes.

Specifically, they will monitor employee stress, burnout, job and life satisfaction, health, sleep, general energy use, and travel. Researchers will also look at changes to workplace culture, gender equality, and productivity levels.

"We’ll be analyzing how employees respond to having an extra day off . . . The four-day week is generally considered to be a triple-dividend policy – helping employees, companies, and the climate. Our research efforts will be digging into all of this," Schor said.

Companies taking part in the program are confident in a successful outcome, as many previous trials show. They also cite the pandemic as shifting their thoughts on workplace attitudes.

"We have long been a champion of flexible working, but the pandemic really moved the goalposts," said Ed Siegel, chief executive of Charity Bank in the U.K., told The Guardian.

"The pandemic [has] made us think a great deal about work and how people organize their lives," Sienna O'Rourke, brand manager at London-based Pressure Drop Brewing, told CNN. "We're doing this to improve the lives of our staff and be part of a progressive change in the world."