The original source of this appears to be a survey performed by vouchercloud (https://www.vouchercloud.com/blog/office-worker-productivity/ https://www.voucherc

The original source of this appears to be a survey performed by vouchercloud (https://www.vouchercloud.com/blog/office-worker-productivity/ https://www.vouchercloud.com/blog/office-worker-productivity...). Interestingly, the "2h 53m" value is claimed to be the average value reported by the 1989 "UK office workers aged 18+" surveyed. The survey also included a list of non-work activities and asked for each activity (a) whether they were guilty of spending time on that activity, and (b) if yes, how much time they spent. For example, 19% spent time searching for new jobs, and of those who spent time searching for new jobs the average time spent was 26 minutes. These add up to a mere 94 minutes of "wasted time" per day, suggesting that either respondents severely underestimated the time they spent working, severely underestimated the time they wasted, or there's another 3.5 hours/day of time spent non-productively on things other than the 10 options listed in the survey.