The Over and Underperforming, 2010 edition

Last year I wrote a couple pieces on trying to measure team performance vs. expectations.  I came up with a system, and used 1999-2008 data to develop a benchmark for comparison.  After the end of the 2009 season, I meant to evaluate the year’s performance, but could not bring myself to revisit the season without weeping uncontrollably.  Now that 2009 is becoming a distant memory, I can finally face my fears.

To briefly summarize my logic: I am using each game’s spread as a means to measure team performance.  Not the team’s performance against the spread, rather whether they win or lose compared to what the spread predicts.  For each team, I am averaging the spreads for each game that had an upset.  For example, if this year Michigan pulls off upsets with spreads of 4 and 6, and loses one where they were favored by 8, in 12 games, the average is -.17.  Note that we are only including games with a line, i.e. no baby seals.  This is important because Michigan’s 2007 numbers do not include the HORROR, which would obviously make a huge difference. 

Using data from 1999-2008, I found that this average follows a pretty good linear trend when plotted vs. the predicted win % for each team.  Comparing variance from the trend line then tells one a little bit about how the teams are performing; teams above the line are beating expectations, below are not matching up:

So for 2009, I compared results versus this same trendline.  We will start with the Big 10:

Purdue, who has historically the worst numbers in the Big 10, took a giant step into the middle of the pack … however it looks like they are already getting back to true form this year.  OSU is strong as always, and once again Northwestern is at the top by a long shot.  Every year, Northwestern seems to beat expectations, and nobody notices.  I blame it on all that purple; how can anyone take them seriously?

Here is how the rest of the league compares.  Starting with the bottom:

Vanderbilt just edges Tulsa to take the prize.  Vanderbilt was only expected to win 3 games, and managed to only get 1 (take that, Rice).  It was upset by Miss State and Army.  It’s interesting to see Oklahoma and USC so low in a section usually dominated by bottom feeders.

And here are the over-performers:

Southern Methodist handedly takes the crown by winning 3 upsets with spreads over 10 points.  Boise State, who usually is at the top, still isn’t far behind.  Say what you want about them, they always manage to take care of business.  And finally, somehow Bama manages to beat the already lofty expectations for them.

How do these results look over time?  Here is a plot of Michigan, Michigan State, and Ohio State:

Again, recall that this does not include the HORROR.  If it did, one would see that Michigan has pretty much spent the past 5 years not getting it done.  State is very spastic; no one is ever sure when Sparty will Sparty itself.  And OSU has been pretty consistently outperforming since Tressel arrived on the scene.

So what does it all mean?  I don’t know, I was hoping you all could tell me.  It certainly doesn’t help Michigan to have these strong starts followed by a weak Big Ten performance.  That’s what’s hurting MSU in several of these years shown: great start leading up to a loss to Michigan, and implosion afterwards.  For the most part, these numbers confirm what I thought about some of these teams, but there are a few surprises.  Also, Southern Methodist and Northwestern would like your respect.  Please.