Measure outcomes and outputs, not time on the clock.

I while back, I had a pretty good boss, with an annoying habit.  He really measured and remembered people's performance based on the time each person left work each day.  He wanted to make sure people were "putting their time in"  and "not shortchanging" the company.

Mind you, this was a floor of executives directing the efforts of field offices, so there really wasn't a correlation between time your left the office and the performance of their field offices.

How many similar things are you watching instead of the outcomes and outputs?