Anecdotes Aside, Trouncing Opponent in Game 1 of NBA Playoff Series Usually Presages a Series Win

Watching the closing minutes of last night's 119-90 Oklahoma City Thunder thumping of the L.A. Lakers in the teams' opening game of their NBA playoff series, I was reminded of two other Game-1 blowouts in NBA playoff history.

In what is known as the "Mother's Day Massacre" of 1982, the Boston Celtics routed the Philadelphia 76ers 121-81 to open that year's Eastern Conference finals. Yet, Philly took the series in seven games.

Three years later, the Celtics opened up the 1985 NBA Finals with a 148-114 thrashing of the Lakers, the "Memorial Day Massacre." Again, though, it was the team on the losing end of the massacre that ultimately prevailed, as L.A. hoisted the championship trophy.

Judging by these two precedents, therefore, this year's Laker squad didn't seem to be in such bad shape, after all. Rather than go purely by anecdote, however, I decided to investigate all opening games of NBA playoff series since 1982 (i.e., roughly the past 30 years) in which a team won by 25 or more points, to see how often that team ultimately lost the series. (I only examined 4-out-of-7 series; the NBA used to have 2-of-3 and 3-of-5 opening rounds.) The Wikipedia's year-by-year NBA playoff summaries supplied the necessary data. Here is what I found.

Well, what do you know? From 1982 forward, there have been 27 playoff opening-games in which one team triumphed by 25 or more points (excluding this year's Thunder-Lakers game, as the series is incomplete). And in 25 of those 27 series (93%), the team that won easily in Game 1 went on to win the series. In other words, the two counter-examples I initially came up with (the 1982 Sixers-Celtics and 1985 Lakers-Celtics series) were the only two exceptions to the larger trend.

Apparently, the outlook for this year's Laker squad is a lot worse than I had thought!

In thinking that a team that gets blown out in Game 1 has a good chance to win the series, I appear to have succumbed to what is known as the "availability heuristic." Because the 1982 Sixers' and 1985 Lakers' comebacks against the Celtics were so dramatic, they stuck in my mind (i.e., remained available) and evidently led me to overestimate the frequency of overcoming an opening-game disaster.

The late Amos Tversky, a co-developer of hot hand research, also launched the research on availability with his longtime collaborator Daniel Kahneman.