Originally Posted by Pony Boy
I'm not sure this shows that closers don't matter. This just shows average winning percentage for teams with leads of 1-3 runs. Presumably, teams with good closers have winning percentages above the league average and teams with bad closers have winning percentages below league average; when the team leads by 1-3 runs in the 9th. That difference in winning percentage would add up to quite a few games over a 162 game season.
Except teams didn't even use "closers" before the 80's really. Yet the rates were exactly the same.