No data, just anecdotes and my own sense of experience.
Note that I'm not arguing that there is 2 hours wasted in an average day-- rather, I'm arguing that a) mental clarity trumps hours on the job, and b) more time for personal pursuits will lead to more mental clarity at work.
As for the latter question, I expect people to get things done-- but in terms of deciding which things we expect to get done by which date, we need to take some "expected hours per day" into account.
Note that I'm not arguing that there is 2 hours wasted in an average day-- rather, I'm arguing that a) mental clarity trumps hours on the job, and b) more time for personal pursuits will lead to more mental clarity at work.
As for the latter question, I expect people to get things done-- but in terms of deciding which things we expect to get done by which date, we need to take some "expected hours per day" into account.