Looking to resolve a debate... a friend of mine has commented that, in hockey, 'running out the clock rarely works' - i.e. playing to protect the lead is a bad strategy - and I'm pretty sure he's wrong. I've read that 80+% of games this year are won by the team that carried the lead into the 3rd period, so, intuitively, it seems impossible that adopting a defensive posture doesn't work more than half the time. But is there any research to this effect? Is there a way to prove that, yes, playing defense and running out the clock is a good strategy? (And, perhaps, a comparison of this strategy to others?)