I found this CNET article interesting. The benefits of a four-by-ten workweek include lower energy costs, higher retention, higher morale, and higher productivity. It might also improve commute times.
A past study showed changing the lighting improved productivity, albeit temporarily. Reverting it back had the same affect. Productivity improves temporarily because employees feel management cares about their concerns. The affects of the four-by-ten workweek may be termporary as well.
I see resistance from managers who would say “we are already getting ten hours per day out of the employees, so wouldn’t this simply cut off 20% of our productivity?” This one is harder to address, except that productivity drops with number of hours worked. Productivity is hard to measure, but number of hours worked is easy, so managers often opt for the latter as a proxy of productivity. Most execs would continue to work five or six (or seven) days per week anyway.
From an IT perspective, I see this having a positive affect on Change Management and Release Management–longer change windows on the weekend for changes, upgrades, and rollouts. We might expect higher success rates, but to my knowledge this has never been studied.