(NEXSTAR) – Thursday is the new Friday at 38 companies in the U.S. and Canada that are testing out a shorter workweek in hopes of boosting productivity while keeping employees happy.

The companies are participating in a six-month trial working with the nonprofit 4 Day Week Global and researchers at Boston College.

“We establish their baseline before the trial,” explained Joe O’Connor, 4 Day Week Global’s CEO. “So we figure out what their company performance looks like under a range of different metrics like revenue, productivity, energy use, staff turnover, levels of absenteeism and sick leave, and then also their employees’ wellbeing.”

Those baseline levels under the five-day workweek will be compared with levels after testing out the reduced workweek.

Exactly what the schedule looks like at each company may vary a bit, O’Connor said. “Our prerequisite is that it must be genuine work time reduction. So it cannot be four 10-hour days. It can’t be the same hours compressed into four days,” he said.

Most employees will opt for a four-day workweek – and therefore a three-day weekend – when given the chance, O’Connor said. But he noted a minority of employees like to spread out their 32 hours of work across five days, giving them a chance to spend more time with their kids in the morning and after school.

No matter how they cut down their workweek, employers are not cutting back on pay; everyone gets the same salary and same benefits they had before.

The 38 participating organizations employ about 2,200 to 2,300 people, O’Connor said.

Not all 38 companies have decided to go public just yet, explained O’Connor. There are 20 companies and nonprofit organizations who have decided to disclose their participation in the pilot program. They are:

• Advanced RV
• Blue Sky Philanthropies
• CULTIQUE
• Floodlight Invest
• Fresh Squeezed Ideas
• GillespieHall Strategic Communications and PR
• GLIDE Design
• Healthwise
• IPR Denver
• Kickstarter
• Mental Health Advocacy Services
• Montana Nonprofit Association
• M’tucci’s Restaurants
• Own Trail
• Public Policy Lab
• Run for Something
• Seed&Spark
• simPRO
• USENIX Association
• WYNDR

While a four-day week is still rare in the United States, it’s gained popularity in other parts of the world. A study in Iceland involved moving about 1% of the country’s workforce to a 35- or 36-hour week, reports the Washington Post. They found employees loved the shorter week, and productivity either remained the same or improved.

“There is actually a fairly large amount – and growing – of current literature on the four-day workweek,” Timothy P. Munyon, associate professor of management at the University of Tennessee, told Nexstar’s WATE. “The general consensus is that it improves productivity, reduces burnout, and increases respite.”

O’Connor – who works a four-day week, by the way – is confident the participants will see similarly positive results from their trials.