04 February 2012

2011-12 Northwestern Efficiency at B1G Halfway Point

Northwestern is now at the halfway point of conference play.  Its 3-6 record is disappointing and behind where we'd like to see it for NU's NCAAs resume.  But the schedule has been front loaded so the record alone doesn't tell the complete story.  To shed some light on how NU has performed this year by taking into account the schedule we have updated our popular NU efficiency analysis that we discussed last October when we revisited the 2010-11 season.

Before we get into the data it is important to say up front that a sample size of nine B1G games do not a solid statistical analysis make.  To improve the sample size we considered including NU's games against non-conference opponents (excluding cream puffs), but as it turned out the benefits of increased sample size did not outweigh the cost of mixing apples with oranges.  The other caveat we wish to mention is that this analysis is midstream and thus there is more noise in the data from imbalanced schedules across the B1G than there is in an analysis that considers the results from an entire conference season.  In other words it is a little early for this type of analysis but we were curious and figured to share our very preliminary findings.

The statistics on NU's relative defensive efficiency are more significant than those for offensive efficiency although defensive efficiency stats are still only reliable with up to 80% confidence.  When adjusting for differences in game location (home/away/neutral) we found that NU has only performed better than an average defense in the game at Michigan.  NU did have a three game stretch (Penn St, Illinois, at Michigan) in which the defense resembled a typical B1G team, but otherwise it has not been pretty.

The two worst games for the defense have been at Wisconsin (0.25 PPP worse than average -- Carmody still hasn't figured out how to defend Bo Ryan's flex offense) and Thursday's game against Nebraska (0.29 PPP worse than average).  Since Nebraska was the most recent game NU's defensive trend line is substantially negative.  But even if we take out the Nebraska game the stats show that NU's defense is slowly regressing from a pretty poor start at Ohio State (OSU scored 0.14 PPP more against NU than against a typical B1G team).  Or to put all of the above more bluntly NU's defense has been below average on the whole and shows no signs that it will improve as the season wears on.  Bummers.

On offense the statistics are less significant but at least they tell a more optimistic story.   NU's offense has been remarkably consistent within conference so far.  In 6 of the 9 games NU has performed within 0.1 PPP of that of a typical B1G offense.  Otherwise in 2 games NU's offense really clicked (MSU +0.32 PPP, Nebraska +0.22 PPP) and it really bombed at Minnesota (-0.2 PPP).  What we see is that on the whole NU has had a solid B1G offense.  What we can expect to see the rest of the way is unclear.  Not only are the statistics not very significant but the trend line varies between slightly positive and slightly negative depending on whether the Nebraska game is included in the sample.

When one considers NU's offense and defense together you find that NU has had two real stinker games (at Minnesota and at Wisconsin) and one very good game (Michigan State).  Of the nine games, NU has played above an average B1G level in just two games (add in the Michigan game -- which in retrospect helps to explain our editor's rant) and played below average in seven games.

One last point: on average across the nine games NU is 0.07 PPP below an average B1G team.  Since the average B1G team is going to be NCAAs bound this says to us that NU has a good amount of work to do but really is not that far off from where they need to be in order to get that elusive NCAAs invite.  Very preliminarily.  So there.