Thursday, January 24, 2013

Oddball Statistic

I've recently been modifying my data collection to include the score by halves, and in looking at the data, I discovered this oddball statistic: Only 11 NCAA teams average more points in the first half than in the second half:

Loyola (MD)  (#2 MAAC)
Charleston Sou. (#1 Big South, South)
New Mexico St. (#3 WAC)
Indiana (#2 Big Ten)
La Salle (#5 Atlantic Ten)
Oregon (#1 Pac-12)
Oregon St. (#12 Pac-12)
Holy Cross (#3 Patriot League)
Kansas (#1 Big-12)
Lehigh (#1 Patriot League)
Saint Louis (#10 Atlantic Ten)

With the notable exceptions of Oregon State and St. Louis, these are all good to excellent teams.  What's the connection?  Why do almost all teams score more in the second half than in the first half, and why would the few that don't be generally better than average?

4 comments:

  1. Scott, in the second half the trailing team will play at a faster pace in an attempt to catch up and late in the game will also foul often producing more possessions and lots of free throws for the leading team (higher efficiency).

    As to why those teams are better in the 1st half, my guess would be mostly random variation but also perhaps lots of blowouts (no incentive for trailing team to play faster or foul as much) or maybe closely contested games where neither team needs to play catch up.

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  2. I suspect you're right about pace and free throws, although right now I don't have the data to tell.

    Interestingly, the average absolute MOV for the first half (4 points) is greater than the second half (3.1 points). I don't know what that implies.

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  3. Did some quick research, most of the effect is actually efficiency and not pace.

    Overall, there are about 2 more possessions in the 2nd half than the 1st (66 to 64), but efficiency increase from 0.97 pts per poss in the 1st half to 1.08 in the 2nd half. So scoring goes from 62.5 points in the 1st half to 70.8 in the 2nd and about 3/4 of that is due to efficiency.

    Taking out the last 5 minutes of each half, pace is nearly identical but efficiency is still about 1/10th of a point higher per possession. I have no idea why.

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  4. The pace change not happening until the last 5 minutes makes a lot of sense - you're not going to panic into pressing the pace until close to the end of the game.

    The efficiency change is very curious, though. Is this because shooting percentages are better?

    How did you do this research? Is the data readily available?

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