Friday, January 28, 2011

Conference Differentials, Part 11/01/28

The View From Week #3+...
The Big East members have run through 44% of their conference schedules. There is quite a bit of the regular season ahead (Villanova fans should remember how this point last season differed so much from the end of the Wildcats' season), but the conference rankings are starting to take shape. Using the differential of each team's offensive and defensive efficiency can give us an idea of how each team is progressing. The table below reflects conference games through January 27, and for each team, shows their Big East record, their differential, a Pythagorean Winning Percentage (PWP) -- conference games only -- each team's conference strength of schedule rating and SOS rank. Like the differential, the Pythagorean Winning Percentage (PWP) often restates the Win/Loss percentage, but there are (more) often exceptions that can provide insight on how the team is faring with their schedule.

TeamWLPct.Diff.Win %RtgRnk
West Virginia430.5710.0650.6770.826814
Notre Dame630.6670.0010.5020.90532
Seton Hall360.333-0.0570.3380.89068
South Florida270.222-0.0780.2980.89725
St. John's450.444-0.0790.2870.89725

I have sorted the data by efficiency differential, and the movement from last week suggests that a particularly good or bad outing (or two) can have an impact on team ranking. The offensive/defensive conference average is about 1.04 (points per possession), about 0.03 above the Division 1-wide average of 1.01. Is the Big East's offense better or is the defense poorer? Since the average overall conference efficiencies (all games) are 1.08 (offense) and 0.96 (defense), comparatively the Big East's offense is the stronger element. Defense in Big East games is a premium.

Not All 5-2 Records Are the Same
The conference is separating into tiers by differential, one that does not necessarily correspond to conference won-loss records. Pittsburgh (to a lesser degree Villanova) and DePaul are separating from their conference mates, only in different directions. For Pittsburgh and Villanova, there is always time to stumble (see last week) and head back into the pack. For DePaul however, the gap appears to widen with each week. If the differential (consistent with the won-loss record in this case) is a reliable indicator, the Blue Demon Nation will have to wait until next season for (positive) signs of rebuilding. The Panthers and Villanova, despite stumbles this past week, have put some daylight between themselves and the rest of the conference. The cluster of Marquette, Louisville, Connecticut and West Virginia have similar differentials but records that range from 5-2 down to 4-4. If this conference SOS is reliable and the explanation for the differences lies in the set of opponents, expect that section of the conference race to tighten in the next few weeks. Notre Dame, no matter which set of calculations I use, appears to have run through a tough stretch of their schedule. This may be the season when the Irish do another bounce back into the conference's top tier, as hinted by their win in Pittsburgh this week. Surprisingly, Notre Dame's offensive efficiency (1.057) is just above the conference average, while their defense (1.056) is just below. Historically Notre Dame's offense has been among the most productive and efficient in the conference while their defense has lagged seriously behind. Regressing their efficiencies to the mean against their 2011 schedule (so far) has, frankly to my surprise, produced a 0.667 record. Defense trumps offense, perhaps?

Another Look at Strength of Schedule
A few emails with the publisher of Rush the Court and a quick rereading of Ken Pomeroy's Strength of Schedule calculation (based on adjusted offensive and defensive ratings) gave me another approach to express each team's strength of schedule for conference games. The approach is the same used by Pomeroy, but I applied Pythagorean Winning Percentage to the average of the adjusted ratings (offensive & defensive) for each team's opponents. After comparing Pomeroy's Overall SOS and out of conference SOS (a "conference" SOS would be the other component to his overall SOS), I think these numbers pass an eye-ball test, so I went ahead and ranked the teams by their conference SOS. That the teams towards the bottom would appear to have harder schedules makes sense. Teams at the top appear to have easier schedules, which would make sense because their slates contain teams from the lower division. Which makes those exceptions, Georgetown (4-4, SOS #16), Notre Dame (6-3, SOS #2) and Seton Hall (3-6, SOS #8) for example, points of focus when considering how the conference races are unfolding.

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