Sunday, October 24, 2010

Run Hoyas, Run? Part 2

Last time, I discussed the distribution of Georgetown's possessions last season as a function of possession length.*  Today, I'm going to look as the efficiency of Georgetown's offense (and defense) as a function of possession length.  Then, I'll combine the two to find if the Hoyas were leaving points on the table.
*here, possession length = time until first action; see previous article for details.

A few years ago, Ken Pomeroy posted a plot of possession efficiency for each second of possession length, derived from five years of play-by-play stats for Division I college basketball.  I re-posted that figure last time, so here I'll just show my re-plot of his data, along with possession efficiencies for three-second aggregate bins (0-3s, 3-6s, etc.) as I did last time for possession length:

For now, just focus on the solid gray line, which represents Ken's original data - I'll come back to the bins further down the page.

As Ken discussed in his original article, there are three areas of interest on the figure:
  • For possession lengths less than 12 seconds, there is a large increase in scoring efficiency compared to possessions that last longer.  There is a sharp peak at 3-4 seconds (typically fast breaks after steals) where the average D-I team is scoring better than 1.2 points per possession (ppp) - and remember that a middle-of-the-road team will likely average right at 1.0 ppp overall.  However, the improved efficiency drops slowly from the peak, and finally reaches that 1.0 ppp baseline only at 12 seconds into the possession.  Teams benefit greatly from scoring off the break, but continue to benefit well into the possession time as the defense scrambles to get set.
  • For possession lengths of 12-30 seconds, there is very little variability in efficiency, as teams average 1.008 ± 0.010 ppp (yeah, I'm actually reporting a standard deviation here - get over it).  There is a slight reward for scoring earlier in the possession:  12-24 seconds into the possession, teams average 1.013 ± 0.005 ppp, while 24-30 seconds into the possession the average drops to 0.996 ± 0.007 ppp.  It's a subtle and not statistically significant difference.  Here, we've effectively reached an even match between the offense and defense.
  • For possession lengths greater than 30 seconds, efficiency decreases quickly with added time.  As the last few seconds wind off the shot clock, scoring efficiency approaches 0.8 ppp, which is a very poor number.  By now, the defense holds the advantage, as the offense loses its selectivity in an effort to get any sort of shot up at the basket.

So how did the Hoyas and their opponents fare compared to Ken's aggregate? 

(more after the jump)

Wednesday, October 20, 2010

Run Hoyas, Run?

Edit:  Part 2 is now posted.

When John Thompson III took over the Georgetown Hoyas for the 2004-5 season, he installed his version of the Princeton offense which quickly developed the reputation for its plodding pace.

Whether Georgetown can (or has) increased the pace at which it plays has been discussed here before, but I thought I'd post a quick recap, looking at the JT3 era:
Season        Adj. Pace      Rank  
2004-5          60.4        322/330
2005-6          58.7        329/334
2006-7          59.9        328/336
2007-8          62.2        316/341
2008-9          63.6        285/344
2009-10         66.9        188/347
After placing in the bottom-10 nationally for the first three seasons, the pace of the Hoyas' offense has begun to ramp up, until last season the team was just a hair below the median for all of college basketball.  Call it the Roy Hibbert effect (early years) or the Chris Wright effect (later years), but last year's Hoyas are not your older brother's, at least in term of the speed of the offense.

I thought it might be interesting to dig a little deeper into last year's stats, to try and understand how Georgetown was picking up the pace, and whether it was paying dividends.  To do that, I'll refer to an old post by Ken Pomeroy, where he presented a nifty plot showing the distribution of time-of-possession for all NCAA teams and their efficiency at each time (click any figure to enlarge):

This figure was lifted from Basketball Prospectus

The red line, plotted on the right y-axis, shows that possession times are not normally distributed, but rather tend to skew to shorter times.  This is rational behavior, due to the info from the blue line, plotted on the left y-axis.  Shorter possessions have higher scoring efficiencies, mostly due to fast break opportunities (the big hump on the far left of the curve).  As possessions stretch out past 30 seconds, teams become much less likely to score. 

(how this relates to Georgetown after the jump)

Tuesday, October 19, 2010

Signs of life (although not here)

Been getting a few inquiries as to whether we will be bringing the heat again this season.  Rest assured that we are still around, although life has been a bit busier than we'd like.

We - and when I say we, I mean Alan, who wrote all of our comments - did participate in a Big East bloggers round table discussion recently, organized by The East Coast BiasPart one is now up, which gives the bloggers' aggregate guess at finishing order in the conference, and Big East POY and FOY.