The Best Home Court Advantage You’ve Never Heard About

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:

(source: freshmilc.com)

(source: freshmilc.com)

Behind the other three sides, however, looms the massive darkness of the rest of the Jadwin dome:

(souce: goprincetontigers.com)

(souce: goprincetontigers.com)

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:

Screen shot 2013-03-08 at 12.11.41 PM

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.

Screen shot 2013-03-08 at 12.19.32 PM

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.

About these ads
This entry was posted in NCAA Basketball. Bookmark the permalink.

13 Responses to The Best Home Court Advantage You’ve Never Heard About

  1. PLM says:

    I think two things are worth investigating before concluding there is an abnormal HCA for Princeton:

    1) Has this effect resulted in an actual excess home court advantage for Princeton? (Look at home/road point differentials for last 10 years in conference games only).

    2) Does Princeton’s shooting pct. also suffer at home (vs. expected)?

  2. Yeah, I’ve done the research on point 1. Their HCA has consistently hovered in the 5-6 pt range, while other Ivies are in the 1-3 pt range. I looked at the shooting stuff a long time ago, and it seems like John probably has the stats at hand faster than I can pull them again, so I won’t opine on that.

    • Matthias Kullowatz says:

      I think question 1 up there was my question, too. Does Princeton’s home-court advantage on opponent’s threes and throws exceed that of “normal” home court advantages?

      So your data is saying that other school’s in the Ivy league only reduce their opponent’s 3-point percentage by about 1-3 percentage points?

      Thanks!

  3. Matthias Kullowatz says:

    As a side note that might not be all that interesting to people outside the northwest, Spokane’s Whitworth College (Division III) plays in a similar arena, though smaller. It’s like an airplane hangar. Perhaps not coincidentally, they have a pretty remarkable home record over the past five seasons.

  4. John_in_Pasadena says:

    I wonder if there is evidence of the same advantage for the Lady Tigers?

    • mrjames2006 says:

      Great point. I need to cobble together that data. Would be very interesting to look at the women’s side.

      As for HCA, points mere mean that you’d take the neutral court margin expectation and then add HCA for the home team. So, if Princeton were even with a team on a neutral court, it would be -5 or -6 at home and +5 or +6 on the road, given the calculated HCA.

      • PLM says:

        Hmm. If you look at Princeton’s home/away point spreads this year, they have averaged 7-7.5 points difference — as opposed to the 10-12 pts. Michael James is saying is fair value. It would be totally possible the betting market has been misvaluing HCA for this team, but that should show up over time in ATS performance. Looking at all games since 1997, Princeton has gone 197-176 ATS (52.8%). Looking at home games only, they have gone 95-96 ATS. So if anything, it appears the betting market has overrated Princeton’s HCA historically. Odd.

  5. Josh S says:

    Another quirk:

    Although there might not be enough data, I wonder if the disparity in 3-point shooting diminishes as opposing players get older and adapt to Jadwin? i.e. does an opposing senior, after three previous visits to Jadwin, have a better shooting percentage (all else controlled) than does a freshman?

  6. Genser95 says:

    Interesting stuff. A couple editorial things though. Jadwin is not on the Delaware River…there is a canal and a lake down the hill, but the river goes through Trenton, well south. Also, the greatest basketball player in Princeton history never played in Jadwin, since it wasn’t completed until the 1969-70 season (17 years before the three-point line).

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s