Monday, February 16, 2009

Looking back - The new three point line in college basketball

Note: All data referred to is accurate as of 4pm Saturday Feb 14th, because that's when I started running the numbers.

Following the 2007 NCAA Basketball Tournament, the rules committee decided it was time to move back the three-point line. Not to the NBA distance, or the international distance, but who's counting. The women's line remains at the original spot, creating the odd look on collegiate floors across the country.

The goal of this shift was two completely different things depending on who you ask. One answer was that shifting the line back would lessen congestion in and around the lane, and provide quicker and more interesting game-play with room to operate.

The other answer is that everyone and their mother thought they could shoot the old three, leading to boring, low-percentage chuck-fests which were a pretty poor display of the game, so moving the line back should be a deterrent.

So I decided to do a direct comparison between last year and this year in terms of three-point shooting, to see if there's been a notable shift. I looked at makes and attempts on a per-game basis, standard 3Pt%, and the percentage of a teams points that come from made three point shots.

Summary results are as follows. In general, the high and low are outliers, so note the three middle categories.

One thing you can definitely say from this data is that those in the second line of reasoning for the rule change were entirely correct. Attempts, makes, and the trey's importance in a team's scoring are all down this year. At the same time, overall percentage still dropped, so maybe there's still some adjustment to be had in strategies, and usage could drop even further.

On the whole these numbers more that anything else just reinforced what was expected, but some of the other trends I noticed in the process were also interesting:

- Out of the top 25 teams in attempts per game each year, only one team in 07-08 and two teams in 08-09 are actually in the top 25 in three-point percentage.

- In 07-08 Utah State managed to be in the 10th highest percentage shooting team despite being in the bottom 25 of more than 340 teams in attempts. No such anomaly occurred in 08-09.

- In both years, the corelation between reliance on the 3pt shot and overall points per game was less than 5%, or negligible at best. 3P% held a higher correlation to points, around 45% both years, but still not a damning cause-and-effect.

- Nationwide variance in 3pt percentages jumped more than 25% from 07-08 to 08-09, while the range of percentages increased more than 35%, though standard deviation only increased 12%

If anyone is interested in playing with the numbers in a more mathematically savvy way than I have, here's my source data: [Download]

1 comment:

Stamford Talk said...

Not very dramatic changes, but I think that's a good thing, right? Interesting article nonetheless. And now I am totally in the mood for some March Madness.