After six months, most of the 33 companies and 903 workers trialing the schedule
With no reduction in pay, are unlikely ever to go back to a standard working week
None of the 27 participating companies were leaning towards or planning on returning to their former five-day routine
About 97% of the 495 employees who responded said they wanted to continue with a four-day week.
The majority of companies taking part in the trial were based in the United States and Ireland.
Those responding to the survey rated their overall experience 9 out of 10, based on productivity and performance.
Workers were equally positive about the trial, reporting lower levels of stress, fatigue, insomnia and burnout, and improvements in physical and mental health.
The trial was also good for company earnings
Average revenue rose 38% when compared to the same period last year, according to the survey.