Is Miami's 19-Point Win Versus San Antonio Historically Significant?

Miami's 19-point victory on Sunday was the largest margin of victory in a Finals series in the past three seasons. Somehow, the series seemed to have tilted way in favor of the Heat in a little more than a quarter's worth of playing time. The blowout victory was a revelation for the Heat, who made the necessary adjustments in the second half to take a commanding lead on the way to winning Game 2. With the series tied at 1-1, Game 3 has historically been the pivotal game on which a Finals series hinges.  

Can margin of victory predict the Finals winner?

As CBS sports columnist Gregg Doyel wrote, "Since the NBA Finals went to the 2-3-2 format in 1985, the series has been tied 12 times entering Game 3. In those 12 series, the Game 3 winner has gone on to be the champion 11 times."  That's a stat worth paying attention to, or maybe it's a stat just stating the obvious; that championships are not necessarily caused by winning Game 3 itself, but rather in the probability that the better team will win more games. Game 3, all things being equal, has a greater chance of  being won by the better team, and therefore, why the champion wins Game 3 more often than the loser.   

So how about turning our attention to margin of victory? Does the margin of victory in a single NBA Finals game provide a clue into who will win the championship? 

The thinking is that the better team will have a more dominant performance that manifests itself in larger margins of victory. After all, it's rare that an eventual champion would lose in a blowout if they indeed are the better team. Great teams humble lesser teams, and lesser teams rarely have the firepower to beat great teams by more than what great teams can beat them by over the course of a seven-game series. 

Looking at margin of victory data going back to the 1990 NBA Finals -- a span of 23 Finals --  the team with the largest margin of victory in a single game would eventually claim the championship 19 times. 

In addition, only three champions since 1990 have lost a Finals game by more than 13 points; the 1996 Chicago Bulls (21), 2000 Los Angeles Lakers (33), and 2005 San Antonio Spurs (33). The team that lost by 13? That would be the 2006 Miami Heat who lost to the Dallas Mavericks. It should be noted that the 1996 Bulls lost Game 4 by 21 after building a 3-0 series lead against the Seattle Supersonics, and the 2000 Lakers lost Game 5 by 33 after opening up a 3-1 series lead against the Indiana Pacers. The 2005 Spurs lost Game 4 by 33 to the Detroit Pistons to make it a 2-2 series.

From the data, we can infer that if this year's version of the Spurs win the series, they will become only the fourth team since 1990 to win the championship after losing a Finals game by more than 13 points. If the Spurs do not beat the Heat in a game by 20 or more points, they will become just the 5th team in the past 24 Finals to win the championship without having the largest margin of victory in a single game. 

The data seems to suggest that better teams more often than not display the most dominant single-game performances in a series. Miami has staked a claim for most dominant performance in this series, but of course, the series is still in its infancy as the Spurs and Heat play the next three games in San Antonio.