# From the Live Blog: Baseball Haterade (With NFL Regression Tangent)

[For ease of reference—with apologies to those of you who sat through or otherwise already read my NFL Live Blog from this Sunday—I’m once again splitting a few of the topics I covered out into individual posts. I’ve made mostly made only cosmetic adjustments (additional comments are in brackets or at the end), so apologies if these posts aren’t quite as clean or detailed as a regular article. For flavor and context, I still recommend reading the whole thing.]

In support of last night’s screed [Why Baseball and I are, Like, Unmixy Things], especially the claim that “[MLB] games are either not important enough to be interesting (98% of the regular season), or too important to be meaningful (100% of the playoffs),” here’s a graph I made to illustrate just how silly the MLB Playoffs are:

Not counting home-field advantage (which is weakest in baseball anyway), this represents the approximate binomial probability [thank you, again, binom.dist() function] of the team with the best record in the league [technically, a team that has an actual expectation against an average opponent equal to best record] winning a series of length X against the playoff team with the worst record [again, technically, a team that has an actual expectation equal to worst record] going in.  The chances of winning each game are approximated by taking .5 + better win percentage – worse win percentage (note, of course, the NFL curve is exaggerated b/c of regression to the mean: a team that goes 14-2 doesn’t won’t actually win 88% of their games against an average opponent. But they won’t regress nearly enough for their expectation to drop anywhere near MLB levels).  The brighter and bigger data points represent the actual first round series lengths in each sport.

By this approximation, the best team against the worst team in a 1st round series (using the latest season’s standings as the benchmark) in MLB would win about 64% of the time, while in the NBA they would win ~95% of the time.  To win 2/3 of the time, MLB would need to switch to a 9 game series instead of 5; and to have the best team win 75% of the time, they would need to shift to 21 (for the record, in order to match the NBA’s 95% mark, they would have to move to a 123 game series.  I know, this isn’t perfectly calculated, but it’s ballpark accurate).  Personally, I like the fact that the NBA and NFL postseasons generally feature the best teams winning.

Moreover, it also makes upsets more meaningful: since the math is against “true” upsets happening often, an apparent upset can be significant: it often indicates—Bayes-wise (ok, if that’s not a word, it should be)—that the upsetting team was actually better.  In baseball, an upset pretty much just means that the coin came up tails.