How Important Is Home-Court Advantage in the NBA?

Kevin Belhumeur@webb5008Contributor IIFebruary 8, 2013

Home-court advantage may determine how the West is won in this year's postseason.
Home-court advantage may determine how the West is won in this year's postseason.

With more than half of the NBA regular season complete, conference seedings begin to capture the attention of NBA fans league wide. Contending teams raise their intensity as they jockey for playoff position, trying to secure home-court advantage in the postseason.

Of the four major American sports, home-court advantage is most meaningful in the NBA, with teams consistently winning around 60 percent of their regular season games in their home arenas.

But does this trend carry over into the playoffs? 

Statistics drawn from NBA.com help answer that question with a resounding yes. In fact, the following numbers show that is it harder to win on the road in the postseason than it is to win on the road in the regular season. 

From 1998-2008, home teams in the regular season won 7,021 games while losing 4,569 games for a winning percentage of 60.6.

During this same period of time, home teams in the postseason won 513 games while losing only 278. The winning percentage in the playoffs for home teams was 64.9 (more than four percentage points higher than it was for home teams in the regular season).

However, some of this disparity can be explained away by the nature of playoff seeding. The teams finishing with better regular season records are the ones given home-court advantage in the postseason.

Therefore, it is difficult to determine how much of a team's home-court success can be attributed to the fans and the arena as opposed to the fact that they are simply the better team in a particular matchup.

To try to answer some of the differences between playing on the road and playing at home, let's analyze the statistics:

When at home (between 2003-2011) compared to on the road, teams decreased their turnovers by 3.1 percent per game, increased scoring by 3.4 percent, increased fast-break points by 12.7 percent and decreased fouls committed by 4.7 percent.

What explains the large disparity in home and away numbers?

Referee bias and the psychological impact of playing at home are two of the biggest factors.

Studies have show that when a crowd is vocal, it impacts the way referees call a game. Albeit subconsciously, referees have historically favored home teams. Between 2003-2011, referees called an average of 22.15 fouls on away teams per game and only 21.13 fouls on home teams.

In addition, the psychological impact of playing at home is a self-sustaining placebo effect: Home-court advantage gives the home team an edge simply because players believe that it does.

Between 1999-2008, a team with home-court advantage in the playoffs won more than three out of four series. In the first round, home teams won series at a rate of 81.3 percent. In the conference semifinals, home teams won 80 percent of the time. In the conference finals, it is interesting to note that the winning percentage dropped to 50 percent. In the NBA Finals, it climbed back up to 80 percent.

Statistically speaking, the best game to steal on the road in a seven-game series is the sixth game, where home teams have historically only won at a 49.2 percent rate.

While referee bias and the psychological impact of playing at home improve the chances of the home team, it is very difficult to determine exactly how much. The impact of home-court advantage on winning, like many other statistical categories compared from one season to another, shows tremendous variance.

In the 2012 playoffs, home teams went a combined 55-29 for a winning percentage of 65.4 percent. Just four years earlier in 2008, home teams went 64-22, combining to post the highest winning percentage in the previous 18 years at 74.4 percent.

Whether you are a big believer in the phenomena of home-court advantage or not, it does statistically exist. To what degree, however, is debatable. 

One thing is for sure though: If given the choice, all 30 NBA teams would rather open a postseason series at home as opposed to on the road.