Tuesday, April 26, 2016

2015 Adjusted Pythagorean Record: Pac-12

Last week, we looked at how Pac-12 teams fared in terms of yards per play. This week, we turn our attention to how the season played out in terms of the Adjusted Pythagorean Record, or APR. For an in-depth look at APR, click here. If you didn’t feel like clicking, here is the Reader’s Digest version. APR looks at how well a team scores and prevents touchdowns. Non-offensive touchdowns, field goals, extra points, and safeties are excluded. The ratio of offensive touchdowns to touchdowns allowed is converted into a winning percentage. Pretty simple actually.

Once again, here are the 2015 Pac-12 standings.
And here are the APR standings sorted by division with conference rank in offensive touchdowns, touchdowns allowed, and APR in parentheses. This includes conference games only with the championship game excluded.
Finally, Pac-12 teams are sorted by the difference between their actual number of wins and their expected number of wins according to APR.
A pair of Pac-12 teams saw their APR numbers differ significantly from their actual records. Oregon finished 7-2 in the Pac-12 despite allowing 40 touchdowns in league play! Meanwhile Washington finished with a losing conference record despite scoring nine more touchdowns in Pac-12 action than their opponents. Close games played a small role in the disparity. Oregon went 3-1 in one-score games, while Washington was 1-2. However, neither was extremely lucky nor unlucky in close games. Turnovers don’t do anything to augment the story, as both had positive differentials in conference play. No, dominating wins and losses explain most of the disparity. While Oregon was still figuring things out early in the season, they lost by 42 points to Utah! That defeat tampers down their numbers. Couple that with the fact that the Ducks were unusually permissive on defense, and you can see why Oregon posted middling APR numbers. On the other hand, while Washington won just four of nine conference games, they were absurdly dominant in three of those wins. The Huskies defeated Arizona, Oregon State, and Washington State by a combined 126 points with no win coming by less than five touchdowns!

Awkward segue.

One of the more interesting developments that has coincided with the Pac-12’s expansion has been the absolute disappearance of Colorado’s homefield advantage since joining the league. The table below lists Colorado’s home and road splits in conference play from their final six seasons in the Big 12 with the same splits over their first five seasons in the Pac-12.
While they were mediocre at home during their last few seasons in the Big 12, their home record was far superior to the duds they consistently laid on the road. However, since joining the Pac-12, their home and road records are effectively the same. Now, some might point out that Colorado’s move to the Pac-12 has corresponded with a cratering of the football program. And to that point, I would 100% agree. In the interest of analyzing this further, I decided to look at a metric that takes into account how well a team is ‘supposed’ to perform and judges them based on expectations, not raw results. I am talking of course, about the Las Vegas line or point spread. For the uninitiated (and churchgoing) audience, the point spread is an unbiased look at who should win a certain game, and more importantly, by how much. Using the points spread, I calculated the Spread Adjusted Margin (SAM) for each Colorado conference game from 2005-2015 and determined the per game averages for their home and away contests. The SAM is pretty easy to calculate. Here are two examples. Say Colorado is expected to beat a team by 3 points. They win by 7. Their SAM for this game is +4. This is, the margin they were supposed to win by (3) subtracted from how much they actually won by (7). Now say Colorado is expected to win by 10 points. Instead they lose by 2 points. Their SAM for this game is -12. That is, the margin they were expected to win by (10) subtracted from how much they actually won by (-2). Easy right? Here are the results separated by their conference affiliation.
As you can see, there does appear to have been a real change since the Buffaloes joined the Pac-12. In their final six Big 12 seasons, the Buffaloes produced a SAM that was almost five points per game better at home. However, in Pac-12 play, the Buffaloes have about the same SAM at home and on the road. I have my own theories (cough cough Marijuana) as to why this might have occurred, but I’d be interested to hear if any readers have (preferably crackpot) theories on why this might be.

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