Don't Call It a Comeback

The greatest comebacks (sorry, LL) in NBA postseason history.

Last night, the Miami Heat rallied from an 11-point deficit entering the fourth quarter to defeat the Milwaukee Bucks 119-114. That got me thinking: What was the greatest comeback in NBA postseason history?

I don’t have play-by-play data for games earlier than the 1997 NBA Playoffs, so I can’t necessarily find the largest deficit a team has overcome in a given game. However, I do have scoring by quarter for every playoff game in NBA history, so I used data from the 1980 NBA Playoffs — the first year the 3-point shot was used — through the 2022 NBA Playoffs* to build models to predict the home team’s win probability after each of the first three quarters.

* I omitted the 2020 NBA Playoffs when building these models, as there were no true home games in the Walt Disney World bubble.

Here are the results of those models, where “homeDiff” stands for the home team’s point differential at the end of each quarter:

• z1 = 0.495935 + 0.107364 * homeDiff

• z2 = 0.390267 + 0.145429 * homeDiff

• z3 = 0.288885 + 0.212477 * homeDiff

The logits (“z”) can then be used to estimate the home team win’s probability:

\(P_H=\frac{1}{1+e^{-z}}\)