Last month, Ctrip launched a rather unusual experiment. They picked 6,000 employees from headquarters and split them into two groups. One group got an extra 45 days off per year—roughly one day per week—no questions asked, no approval needed. The other group carried on as usual. Then they tracked performance, turnover, and satisfaction, handing the data over to professional researchers.
You can think of it as a real-world test: what actually happens when you shrink the work week?
The experiment itself already tells us something: the conversation around shorter hours is no longer just for European startups. It’s becoming a tangible reality in our own backyard.
Some might say, "Great, who wouldn’t want more time off?" Others might argue, "This is naive—some companies can’t even pull off a five-day week, let alone four."
Let’s skip the cheerleading and look at the evidence.
In July 2025, Nature Human Behaviour published what is currently the largest academic experiment on reduced work hours. Led by Boston College, it covered 141 companies across six countries, involving nearly 3,000 employees. The model was called "100-80-100": pay 100% salary, keep 80% of the work time, but still aim for 100% output.
Note: this wasn’t strictly a four-day week. Companies could decide how to trim the 20%—cut a day, shorten each day, whatever worked.
After six months, the results were striking. Most employees reported significant improvements in physical and mental well-being. And 90% of the companies chose to keep the new schedule permanently.
How can you cut 20% of work time and still get the same output?
Here’s the key detail the study revealed. At first, many employees were hesitant to actually take the time off—they worried about falling behind. But over time, their work hours naturally dropped from around 40 per week to 34. Fortune later covered this phenomenon and offered a blunt explanation: "We were already wasting a chunk of that time anyway."
Exactly. Think about all those pointless meetings, the unnecessary reports, the processes everyone maintains but no one finds useful. A lot of "work" is really just filling time—busywork we do to look busy.
In other words, reducing hours doesn’t magically boost efficiency. It forces you to confront a truth that was always there: roughly 20% of a typical work week is spent on fake work. The companies that succeeded weren’t the ones demanding more from employees—they were the ones that finally streamlined their processes.
So what happened to the companies that tried a four-day week? Many of them found that the real question isn’t "can we afford to give people more time off?" It’s "can we afford to keep pretending we need all that time in the first place?"