Showing posts with label schedule. Show all posts
Showing posts with label schedule. Show all posts

Monday, December 27, 2010

Big East preview

The Big East conference season kicks off tonight with a match-up of top-10 teams as the UConn Huskies head to the Peterson Event Center to take on the Pitt Panthers.

The Hoyas don't tip off their conference slate until Wednesday with a tough road game at Notre Dame, so I thought I'd take the opportunity to run through a few of the normal features we run at the end of the pre-conference season, all in one big blog post.


First, Alan joined a number of fellow Big East bloggers in answering a series of questions over at the east coast bias.  Parts one, two and three have already posted, with at least two more to follow this week.  And VBTN takes a look at Big East home/road splits so far in the respective non-conference schedules.


One bit of eye candy we haul out each season around this time is the Big East aerial, which shows the relative offensive and defensive strengths of all of the conference teams right as conference play gets rolling (2008-9 link; 2009-10 link).

Here's how the teams stand right now:

You'll need to read this post to understand everything in this figure, but simply:  upper-right = good; lower-left = bad.


Some observations:
  • Pitt is currently rated as the best team in the Big East, and their doing it mostly with their offense.  This isn't a surprise, as the last great team at Pitt (2009) was also dependent upon their offense.  Right now, Pitt's adjusted OEff is actually higher than the '09 team, mostly due to an obscene 48% off. rebounding rate.  They're also turning the ball over less this season.
  • Pitt, Georgetown and Notre Dame are the most dependent upon their offense, while So. Florida is the only team with a big defensive lean.

Tuesday, February 2, 2010

Conference efficiency margins and strength of schedule

A couple of my favorite basketball bloggers are big proponents of conference efficiency margin (what I normally call net efficiency).  Efficiency margin is simply the difference between points per possession scored and points per possession allowed.

Basketball Prospectus author John Gasaway, who may have pioneered this stat, offered a pithy explanation of it's utility last month:
Why track per-possession performance in league play?

Over the next eight to nine weeks these 126 teams will play over a thousand possessions each. Half of those possessions will take place at home, and half of them will occur on the road. All of that basketball will be played against opponents that by conference affiliation have been designated as nominal equals in terms of programmatic resources. (Though, granted, a league like the A-10 certainly exhibits some notable diversity in terms of member heft.) And, not least, all of that basketball will take place in increasingly close temporal proximity to the NCAA tournament.

And greyCat over at Villanova by the Numbers has been tracking these stats for the Big East biweekly, and in great detail.  Mr. Cat (I actually do know his name, but I'm not telling) also provided an important caveat before jumping into the numbers with his latest posting
I understand the argument against looking only at (for example) conference games -- the sample is too small, the schedule is unbalanced, the time-frame is too restricted, etc. etc. etc. -- all of which are valid points.

I actually took a look at this very point last season around this time, and it turned out to be more more informative than I realized at the time.  I'll come back to why that is at the end, but first I thought I'd re-run that analysis tonight.

I've compiled the strength of schedule for all Big East teams for conference games played so far (through Monday, Feb 1st), and plotted eff. margin against strength of schedule. Here, I'm using KenPom's Pythagorean rating (0-1), rather than his ranking (1 to 347) for the strength of schedule calculation.  The strength of schedule is weighted for home vs. road games.  The efficiency margin stats come from StatSheet.com.

Here we go (click to enlarge):



Just as we saw last year, there is a strong correlation between conference strength-of-schedule played to date and the efficiency margin posted.  So teams such as West Virginia and Villanova, which currently lead the league in efficiency margin are definitely getting some help from a soft early-season schedule, while Seton Hall is a bit below water thanks in no-small-part to a brutal start from the schedule-makers.

Now a bit of that effect is circular, in the sense that good teams don't have to play themselves, and therefore their schedules are slightly easier on average, while bad teams schedules are harder because they're missing an easy opponent (themselves).

However, in any league with an unbalanced schedule like the Big East, these effects are only one part of the overall scheme that won't entirely even out at the end.  For example, our own Georgetown Hoyas have been rewarded this year with home-and-away series with the current AP-ranked #2 and #3 teams.

Here's a table summarizing the conference season so far, and what's left for each team (rankings are from hardest to easiest):
.                      Current           Remaining          Exp. Final
Team                  SOS    Rank        SOS    Rank        SOS    Rank
Cincinnati           0.825    15        0.902    3         0.868    14
Connecticut          0.878    6         0.862    11        0.870    11
DePaul               0.913    2         0.823    14        0.875    6
Georgetown           0.867    10        0.876    8         0.872    10
Louisville           0.882    5         0.872    9         0.877    4
Marquette            0.890    4         0.819    16        0.858    16
Notre Dame           0.856    11        0.892    5         0.875    7
Pittsburgh           0.873    9         0.878    7         0.876    5 
Providence           0.812    16        0.936    1         0.888    1
Rutgers              0.910    3         0.838    13        0.879    3 
Seton Hall           0.919    1         0.819    15        0.872    9
South Florida        0.873    8         0.860    12        0.867    15
St. John's           0.877    7         0.864    10        0.870    12
Syracuse             0.851    12        0.885    6         0.869    13
Villanova            0.845    13        0.911    2         0.886    2
West Virginia        0.839    14        0.897    4         0.874    8 

Seton Hall has had the pleasure of playing the toughest Big East schedule so far, and are showing the effects with a 3-5 record.  They're path will get much easier, so expect them to make a push towards legitimacy.  DePaul and Rutgers have also had tough early-season slates, but I'd think the best they can hope for is just a step up from the absolute dregs of conference efficiency margin (anything worse than -20 is really bad).

Providence has a brutal second-half schedule, harder than what any team has played so far.  Many had pegged the Friars to be one of the worst teams in the league this year due to the loss of so many players, and that result may still be coming.  Meanwhile the Big East's Big Three (Villanova, Syracuse and West Virginia) have all benefited from relatively easy first-halves and should all see things get a bit tougher the rest of the way.  In fact, Syracuse may be in the best position of the three to win the regular-season conference title because of this.

It's also worth noting that the spread between easiest expected final schedule (Marquette) and hardest (Providence) is about the equivalent of the difference between playing U of Miami or UConn on a neutral floor, respectively (i.e. not really that much).


Finally, returning to that bit about what was so informative about last year's plot (reproduced below).  It turns out that teams that met two conditions went on to the NCAA tournament:
  1. They sat above the fitted line, i.e. were better than average, adjusted by schedule strength.
  2. They already had positive efficiency margins midway through the season.
So, right now, it looks like there are seven teams in good position for March (Villanova, West Virginia, Syracuse, Georgetown, Louisville, Marquette (!), and Pitt).  There are three other teams that meet only one of those criteria: Cinci, UConn and Seton Hall.

Here's last year's plot (from 24-Jan-09):

Saturday, January 16, 2010

Once more unto the breach

I can't speak for the rest of Hoya-dom, but the coincidence of the next stretch of games with the date on the calendar brings to mind the dreadful memory of last season's implosion:  on January 16th, 2009, the Hoyas sat at 12-3 (3-2) heading into a road game against stiff opposition (Duke).

We all know how the rest of the season went:  4-12 (4-9).

In the next 5 games, Georgetown plays four of KenPom.com's top-25 (through Friday's games), with three of those games on the road.  Ken's predictions:
.                                    KenPom
Date          Opponent    Rank     Exp. Score
17-Jan      @ Villanova   [22]      L: 75-78
20-Jan      @ Pittsburgh  [25]      L: 60-63
23-Jan        Rutgers     [168]     W: 77-57
25-Jan      @ Syracuse    [6]       L: 68-77
30-Jan        Duke        [1]       L: 67-72

Regardless of what you think about Ken's methodology, the fact is that the Hoyas are likely underdogs in four games the rest of this month, and will likely lose multiple times.  The question, to me, is not how the Hoyas do in this next stretch of five games, but rather how the team responds after this death-march.

To be clear, the remaining schedule is no cake-walk with two tough road games (Louisville and West Virginia) and several other toss-ups.  Indeed, right now Georgetown's RPI strength-of-schedule projects to be #2 at the end of the regular season.

This all got me to wondering how this year is stacking up against last season, at nominally the same point.

My favorite comparison for this sort of thing is performance.  Simply put, I use KenPom's expected point spread, adjusted for the actual pace of the game, and compare it to the actual point spread of that game. That is, if the Hoyas are expected to beat Team A by 10 points, based on KenPom's stats, but actually win by 14 points, the net performance for that game is +4 points.

I usually update the performance charts (linked at upper-right) after each game, but I won't hold it against you if you've never looked.  Here's team performance for last season and so far this year (click on any figure to enlarge):


What's immediately obvious to me is that there's a lot less variability game-to-game.  The 2008-09 team could be tremendous (+20 points above expected against Maryland, Savannah St. and UConn) or lousy (-15 points below expected against West Virginia, Louisville and St. John's (II).  And remember, these expected point spreads are worked out using end-of-season stats (i.e. after the great collapse).

Meanwhile, this season the Hoyas have played every game within 10 points of expectation - their best game was +6 points vs. DePaul, the worst was -9 points vs. Old Dominion.

Allow me to quantify this variability, going even further back for context:
Season        Games          SDev. of Perf.
2007-08       First 17       ±  8.6 points
2007-08       Last 17        ±  9.4
2008-09       First 15       ± 14.6
2008-09       Last 16        ±  9.3
2009-10       First 15       ±  4.3
It looks like typical variability for a ~16 game stretch is around ±9 points; that's to say that most games (about 2/3) should end up within 9 points of KenPom's predicted outcome, adjusting for actual game pace.

As you can see, the early season last year was all over the place.  I'm not sure that was some sort of harbinger of impending doom, but it does show that you never knew what kind of performance Georgetown would bring to each game (despite going 12-3).  Also interesting to me is that the Hoyas only played 2 games all year slightly better than expected (here defined at 0-10 points above expected).  Essentially, either the Hoyas were very good - mostly early in the season - or they just weren't good at all.

So far, this season is another matter entirely.  Most games the Hoyas are performing within ~4 points of what KenPom tells us to expect - good news for gamblers, I suppose.  As the great Dennis Green would say, they are who we think they are.

But why?

As my loyal reader knows, I can never leave well enough alone.  Instead of just looking at net performance, I can also look at offensive performance (points scored - expected points scored) and defensive performance (expected points allowed - points allowed).
.                            SDev. of       SDev. of
Season        Games          Off. Perf      Def. Perf
2007-08       First 17        ±  6.9         ±  5.8
2007-08       Last 17         ±  7.7         ±  6.8
2008-09       First 15        ± 10.2         ±  8.3
2008-09       Last 16         ± 10.5         ± 10.6
2009-10       First 15        ±  7.0         ±  5.7
What we see early (the first three lines) is that the variability of the offensive or defensive performance is less than the overall performance.  That's what we'd expect if the two are uncorrelated or vary together (i.e. when the team is playing well on offense, it's also playing well on defense).

Also, for four of the five cohorts the variability of the defense is smaller than the variability of the offense.  This also makes intuitive sense, along the lines of the baseball adage that "speed never slumps." A several game hot- or cold-streak from outside is much more likely to manifest itself in these stats than running into several hot or cold teams consecutively.

However, starting in the 2nd half of last season, and much more strongly now, we see that the variability of the offense and defense are larger than the overall variability of team performance.  What's happening now is that when the offense is playing poorly, the defense plays well (and vice versa).

Excuse me while I whip this (graph) out:



as compared to previous times:



If I were a clever fellow, I'd be able to tell you why this is happening.  Maybe it's just small sample size.  I don't think it's related to rotations, especially this year (what rotations?).

But if the trend continues, it means that, at the end of the game, Georgetown is performing about what KenPom's stats predict.  And he's predicting a whole lot of pain over the next two weeks.

Sunday, January 25, 2009

Gasaway on the Hoyas

John Gasaway of Basketball Prospectus had a short post on Georgetown Friday, "Georgetown's Internal Bleeding."

Some highlights, annotated:
The Hoyas have now played a third of their conference slate. There’s plenty of season left to be played, of course, but in order to make something of that season GU will have to improve dramatically on defense.
I'd love to have a snarky rebuttal, but this is true. I've updated the season's Performance Charts through the West Virginia game, and the Hoyas have been consistently underwhelming on defense since the UConn game. That's six games in a row where the Hoyas have allowed more points than expected, based on venue and KenPom's season stats to date.
A month ago I remarked somewhat raffishly that Georgetown appeared to be inventing a new category: “outstanding defense without rebounds.” Well guess what. Turns out you need rebounds after all. In a conference with Seton Hall, the Hoyas can at least take solace in the fact that they will always be spared the indignity of being “last in defensive rebounding,” but the truth is their defensive rebounding is terrible.
For the season as a whole, Georgetown's defensive rebounding has been miserable at 61.7%, ranked 318/344 - worst amongst the BCS conference schools. Within conference play, Georgetown (56.9%) is just a fuzz better than Seton Hall (56.4%) which is worst. The comparison to SHU is particularly appropriate since the teams have 5 common opponents so far this season (UConn, NDU, Cuse, Provy and WVU). The only difference is that the Pirates have played Villanova (OR = 36.3%; 69/344) while G'town played Pitt (43.6%; 2/344).
There’s a sense at large that Thompson will right this talented ship and, who knows, that sense may be proven correct. But as of this moment Georgetown has been merely the tenth-best team in Big East play on a per-possession basis. Unthinkable on December 29, but true.
Here's where Gasaway is being a bit disingenuous - Georgetown may be tenth in efficiency margin [= points scored per 100 possessions - points allowed per 100 possessions], but they have played the hardest conference schedule to date, based on KenPom's ratings.

To look at this further, I've compiled the strength of schedule for all Big East teams for conference games played so far (through Saturday, Jan 24th), and plotted eff. margin against strength of schedule. Here, I'm using KenPom's Pythagorean rating (0-1), rather than his ranking (1 to 344) for the strength of schedule calc.



The blue line is a linear fit to the data. There is clearly a trend here - the harder a team's conference schedule so far, the worse their efficiency margin. If the fitted line is to be trusted - and I don't have any way of knowing if it should, beyond the fact that it is statistically significant at 95% - it implies that there are 6 top-tier teams in the Big East, once you account for the quality of opposition. Georgetown is one of them, along with Louisville, Pitt, Marquette, UConn and West Virginia.

One thing I'm not adjusting for here is home vs. road in evaluating strength of schedule, mostly because I'm not clear what the best weighting factor would be. It should be noted that Georgetown has played 6 conference games so far this season, with only 2 on the road.

A few other comments from looking at this chart:
  • Notre Dame is surprisingly (to me) below the line, implying that they are not a top-half team in the Big East.
  • Providence and South Florida are quietly hanging around in the second tier of Big East teams. The Friars aren't a big shock, as they were a darling pick to make the leap this year due to their experience; the Bulls may be reaping the rewards of Gus Gilchrist's eligibility.
  • The four worst teams are Rutgers, St. John's, DePaul and Cincinnati, in descending order. A few weeks ago, I had figured that Cincinnati was probably the 10th best team in the Big East, heading into conference play.
  • Seton Hall, today's opponent for the Hoyas, has played the 2nd hardest conference schedule to date - i.e. they may not be as bad as their current conference record indicates.

Monday, November 5, 2007

News: 2007-8 Basketball Schedule for Geeks

The lads over at HoyaHoops.com have posted an electronic version of Georgetown's 2007-8 schedule, including game location as street address and a list of available media sources.

A Google calendar version is here; a more general .ics version (for importing into other calendar programs) is here.