Microsoft Japan tested a four-day work week. Productivity jumped by 40%

For the month of August, Microsoft Japan experimented with a new project called Work-Life Choice Challenge Summer 2019, giving its entire 2,300 person workforce five Fridays off in a row without decreasing pay.
The shortened weeks led to more efficient meetings, happier workers, and boosted productivity by a staggering 40%, the company concluded at the end of the trial.
“Work a short time, rest well and learn a lot,” Microsoft Japan president and CEO Takuya Hirano said in a statement to Microsoft Japan’s website.
In 2018, New Zealand trust management company Perpetual Guardian trialled a four-day work week over two months for its 240 staff members.
Another experiment published by the Harvard Business Review shows shorter work days, a decrease from the average 8-hour work day to a 6-hour work day, increased productivity.