Monday, February 1, 2010

Big East Aerial Update

At the start of the Big East season, I posted an aerial showing where each of the sixteen teams stood at the start of conference play.

I'll reproduce it here.  This is based on KenPom's adjusted offensive and defensive efficiencies, through games played 31-Dec-2009 (click to enlarge):

Here's an explanation of the plot, cribbed from the first time I ran one of these:
  • Note that the ordinate axis (defensive efficiency) is scaled backwards, from high to low, so that better defensive teams are at the top of the graph
  • I've color-coded the team markers, from black to yellow, indicating the nominal Pythagorean Rating, using Rating = A_OE^11.5 / (A_OE^11.5 + A_DE^11.5)
  • The solid grey line is a sort of 1:1 line, indicating where a team would be equally capable at offense and defense. Teams to the left or above the line are better defensively, while teams below or to the right are better offensively.
  • The diagonal blue dotted lines are isopleths. Teams that are the approximately same distance from a line (e.g. Notre Dame and Seton Hall) should be equally good, although they may do so by different means (here, Notre Dame by offense, Seton Hall by defense). 

Now that a month of basketball has gone by and almost half of the conference regular season is in the books, I thought I'd update the aerial with Ken's stats posted for game played through 31-Jan-10.

Here it is:

A comment for each team, then a table to sum it all up:
  • Cincinnati: In terms of overall ranking (i.e. position relative to the isopleths), they've been treading water for the last month, but they've actually had a nice improvement in off. efficiency that's being offset by a concurrent decrease in def. efficiency.
  • Connecticut:  Another team without a big change in ranking, and here the underlying stats are also stable - DEff is a bit worse while OEff is just a touch improved.
  • DePaul:  Thankfully, the Blue Demons have been playing better this last month on offense - I was worried they were going to fall off the graph.
  • Georgetown:  The Hoyas are rating as a better team now than at the end of December, as they are now touching that isopleth that was just above them on the first plot.  The Hoyas offense has greatly improved over the last month.  Unfortunately, the defense has regressed (about as much as Cinci's), and that is keeping Georgetown from making the leap to truly elite
  • Louisville:  The Cardinals have actually improved over the last month, in spite of a couple of tough losses.  Louisville has the same basic movement as the Hoyas (big improvement on offense somewhat offset by a poorer defense), but at a smaller scale.
  • Marquette:  The unluckiest team in the nation have been playing at the same def. efficiency over the last month as in the early season, but their offense is a bit better so they get a small uptick.
  • Notre Dame:  Speaking of teams falling off of the aerial, the Irish came into conference play with a horrible defense, and it's only gotten worse over the last month.  Unfortunately, their great offense also has cooled a bit so the Irish have begun to slide down the ratings.
  • Pittsburgh:  The early season story in conference was the great start (5-0) that the Panthers got off to, including a win at Syracuse that will likely be very important on Selection Sunday.  They've gone 1-3 since, but even with the swoon, Pitt is rated higher than a month ago thanks to a much improved offense offsetting a weakening defense (are you starting to catch onto a theme yet)?
  • Providence:  The Friars are gaining fast on Notre Dame and USF for the 12th slot in conference, with an improving offense.
  • Rutgers:  "The ship be sinking" on both ends of the court, even accounting for their 1st conference win this weekend over Notre Dame.
  • Seton Hall:  At the start of conference play, the Pirates were a better defensive than offensive team, which didn't jibe with what I expected from South Orange.  Well, the offense has gotten better in conference, but the defense has gotten even worse.  Natural order is restored.
  • South Florida:  Same story as Seton Hall, although the worsening defense isn't quite as dramatic as with the Pirates.  Could this be from the loss of Gus Gilchrist?
  • St. John's:  Leave it to the Redmen to buck the overall trend here.  The Johnnies have taken a major step backwards on offense in conference, and a somewhat improved defense hasn't been able to make up the difference.
  • Syracuse:  The good news?  The Orange aren't quite as good now as they were a month ago.  The bad news?  They're still better than everyone else.  The conference's best defense slips just slightly while the offense is getting less efficient.
  • Villanova:  The Wildcats have shown by far the largest improvement over the past month.  Their offense is much better and now easily the best in the conference while the mediocre defense is sliding up to middle-of-the-pack.
  • West Virginia:  Just a small drop-off in the defense, as the offense holds steady.  The Mountaineers still rate as the second-best team in the league.

And here's the table to quantify my ramblings:

Change in Adj. Efficiencies (31-Dec to 31-Jan)

.                                Net       Rel.
Team            O.Eff   D.Eff    Eff       Net
Cincinnati       3.8    -3.6     0.2      -0.2
Connecticut      0.3    -0.6    -0.3      -0.7
DePaul           0.9    -0.1     0.8       0.4
Georgetown       6.0    -3.4     2.6       2.2
Louisville       3.7    -1.6     2.1       1.7
Marquette        1.4     0.1     1.6       1.1
Notre Dame      -0.6    -1.4    -2.1      -2.5
Pittsburgh       4.3    -2.0     2.3       1.9
Providence       3.5    -0.9     2.6       2.2
Rutgers         -0.7    -0.8    -1.5      -2.0
Seton Hall       4.0    -5.1    -1.1      -1.5
South Florida    4.1    -4.6    -0.5      -1.0
St. John's      -5.0     1.9    -3.1      -3.5
Syracuse        -1.8    -0.9    -2.7      -3.1
Villanova        5.0     1.7     6.7       6.2
West Virginia    0.0    -1.0    -1.0      -1.4

Average          1.8    -1.4     0.4

Hopefully all the columns are self-explanatory, except perhaps the last.  As I alluded to above, the general trend across the conference is for teams to improve offensively while sliding (although not as much) on defense.  I'm not clear if this is real or just an effect of KenPom's adjustments.

In any case, I simply subtracted that +0.4 average Net Eff. from each team's Net Eff. to give a measure of change in team performance relative to the rest of the Big East:  Villanova is easily the most improved team in January.

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