At the WGOM, ubelmann posited:
It would be interesting to chart something like winning percentage for home teams with an R run lead going into the 9th inning vs. season. I feel like I haven’t seen that anywhere? That would seem to be a strong indicator of whether or not modern bullpen usage is better than old-school bullpen usage.
That seemed like something I could jump on.
From 1977 to 2006, WE for th home team with a 1-run lead entering the 8th or 9th inning.
1977 – 1989 (over 40% SV = 1+ IP) – 9 of 14 seasons above average at preserving 1-run leads in the ninth. (2561 out of 2925 – 87.56% of leads preserved)
1990-2006 (over 40% SV = 1 IP) – 4 of 16 seasons above average at preserving 1-run leads in the ninth. (3133 out of 3651 – 85.81% of leads preserved)
An artifact of a more offensive era, or a refutation of the current bullpen template of the closer as a “9th inning only” guy?
I lean toward the former, but it is pretty interesting that there’s a lack of a convincing argument for the modern bullpen.