Ask any player or coach in the Ivy League which gym is the toughest to play in, and you will get a near unanimous response: Jadwin Gymnasium at Princeton University. The Palestra may get (a lot) louder, and the road trip from Manhattan to Ithaca, New York, may be more arduous, but neither compares to the dome on the banks of the Delaware River.
For those of you who have never had the pleasure to watch a game in Jadwin, let me set the scene. On one side of the court, there are about 5,000 typical stadium style seats:
Behind the other three sides, however, looms the massive darkness of the rest of the Jadwin dome:
The vast majority of jump shots taken in Jadwin have no shooting backdrop, just blackness. Numerous players have claimed it is much harder to shoot there. Just last week, Harvard, the 6th-best three point shooting team in the country, failed to make a single jump shot in their five-point loss. But is that true empirically? To find out, I compiled Princeton’s stats for their last six seasons (from 2007-2008 onward). I also compiled their opponents’ stats.
If Jadwin is truly harder to shoot in, we would expect Princeton’s opponents to miss significantly more threes and free throws than their season average. The stats on Princeton’s 87 home games against Division-I opponents since 2007 back up that claim:
Teams are shooting almost 5 percentage points worse on threes at Princeton compared to their season average. Even more remarkably, on unguarded free throws, teams are shooting 3 percentage points worse. Both of these differences are statistically significant (at the 1% level).
Given that teams shoot an average of 13 threes and 18 free throws against Princeton, the Jadwin Effect could be costing them 2.3 points per game.
But perhaps Princeton is just really good at three point defense, and always holds their opponents to lower percentages than the opponents’ average. To test this, I looked at Princeton’s three point and free throw defense on the road.
The Tigers do hold their opponents slightly below average from three on the road, but the difference is no where near statistical significance. The difference in free throw shooting completely reverses.
(Edit: For the record, over the past six seasons, Princeton has shot an average of 38% from three both at home and on the road. The Tigers have shot 73% from the free throw line at home and 71% on the road).
Based on the results of the last six years, Princeton’s homecourt advantage from playing in its peculiar dome is real and significant. This is especially significant because the Ivy League does not have a conference tournament to determine its NCAA Tournament representative, so any team hoping to win must overcome the Jadwin Effect. Princeton has a rich and deep basketball tradition stretching from Bill Bradley to Pete Carril to Ian Hummer. A small but not insignificant portion of that success must be attributed to its quirky home court.