I feel that averages studies like this miss that people who copied off other people's work in the office, and unproductive middle managers, are way less productive than they were before because it's clear now. And that a lot of people are way more productive, but it won't come in averages.
Of course it's the same productivity, were most of them paid for the extra hours of work - no. Were most of them almost required to stay overtime because the economy is doing bad, etc - yes. The corporatism would want to think of people as gears in a machine, yet they're more like the sensors and chips that turn the machines.
