Home-court advantage? Not so much
— -- Remember the Grizzlies-Spurs thriller in December? An instant classic, thick with big men hitting buzzer-beating 3s for each team, 3-point specialists coming up big at the best times and one improbable make after another. It took three overtimes before Memphis prevailed 117-116, creating an unusual scene: a mighty celebration of screaming and hugging Grizzlies, drinking in the victory not before 20,000 elated fans but in front of stunned and bewildered Spurs supporters heading home dejected.
Because this game was in San Antonio.
It's no secret that the home team wins most NBA games -- in no small part what the NBA regular season is for: to earn home-court advantage in the playoffs.
Home court is valuable. Only, interestingly, it's not nearly as valuable as it once was.
Earlier this month, our statistics guru Dr. Steve Ilardi alerted us to this bizarre trend and we've been tracking it ever since.
That Memphis win wasn't a fluke. The hushed home crowd is becoming a thing this season. Home squads are losing all over the place -- including Tuesday night when they lost all six games.
Take a look at the standings. By win-loss record, the Nets, Bulls, Mavericks, Pistons, Rockets, Heat, Bucks, Timberwolves, Magic and 76ers are all performing better on the road than at home. In fact, home teams have won only 53.7 percent of their games this season, the lowest such rate in modern NBA history. And it's not even close.
Asked about the minimized home-court advantage, Rockets general manager Daryl Morey said he was on board with a fairer game that doesn't see inherent advantages for either side.
"For the league, the closer the games, the better," Morey told ESPN.com in a phone interview. "More objective, the better."
This effect is real. And it's changing the NBA as we know it:
• In 1976-77, the home team won a startling 68.5 percent of games. In 2002-03, it was 62.8 percent. Over the past four seasons, the home team's win percentage has fallen steadily from 61.2 to an all-time low of 53.7 right now.
• In two years, home-court advantage has been sliced by nearly a third (28.5 percent), which represents the largest two-year drop in NBA history. From a points perspective, the home team has seen just a 2.2-point advantage this season. We've never seen it this small. Last season, it was plus-2.6. The season before that, plus-3.2.
• This carried over into the postseason. Last playoffs, the home team went 50-39, pulling out the victory in 56.2 percent of the games. That's significantly lower than the historical playoff average that hovers around 65 percent. The home team enjoyed just a 2.8-point cushion last postseason, down from 4.0 in 2012-13 and 4.7 in 2011-12. As recently as 2007-08, the home playoff team enjoyed an 8.1-point edge and won 74.4 percent of all games. Adjusting for pace, the home-court advantage last season was just a third of what it was when the Celtics won the title in 2008 (plus-9.0 vs. plus-3.0).
• This isn't just a midseason blip. Last season, home-court advantage was plus-2.3 through each team's first 50 games, about the same as it is now. It had never been lower than plus-2.6 in the last 15 seasons at this juncture in the season.
• Most striking? In close games, home teams are losing more often than not. In clutch games, when the score is within five points in the final five minutes, the home team has won just 47.7 percent of the 354 games. Here's how crazy this is: Heading into the season, the average win percentage for the home team in clutch games since 1997 was 54.7 percent and never below 51.6 percent. Yes, it's the first time that the home team has not won more than half its close-and-late games. That Memphis game was the rule, not the exception.
• Ten teams have a better record on the road than at home. In the four seasons between 1997-98 and 2000-01, there were no such teams. In fact, the 10 teams this season matches the same total that we've seen in the previous eight seasons combined.
• This is unlikely to be random. The home-court advantage decline over the past two seasons is statistically significant, meaning that the math suggests there is a less than 5 percent chance, given the historical baseline of 3.5 points and 60 percent home win percentage, that this is anything other than a trend.
The question: Why? What the heck is going on?
The short answer: It's not clear. We'd like to hear your theories (see below).
There likely isn't one driving factor that explains the eroding home-court advantage, but a combination of ingredients. After talking around the league, here are three leading theories:
