[Bumped.  Further inquiry into the "Mystery of the Unusually Low Opponents' Free Throw Rate. -KJ]

I've begun to think that the mystery of MSU's low opponent free-throw rate (28.7, #21 in the country according to Kenpom) reflects more than just a conference-wide lack of aggressive offenses (see discussion here for example). Not only does the Big 10 lack teams with a dominant inside game, but it looks as if the refs "let 'em play" more in the Big 10 than in, say, the whistle-happy Big 12 (all stats are for conference-only games through 2/18 from Statsheet.com):

However, within a relatively foul-free conference, MSU is actually one of the more foul-prone teams:

Shifting the emphasis from free-throw rate to foul rate brings a really interesting number into view: opponents' free throw attempts per foul (I could have used a factor to estimate the number of actual shooting fouls committed, but I think it's safe to assume that the ability of one's opponents to hit the front end of a one-and-one is equally distributed across the conference):

The number that really stands out is MSU's .81 Opp FTA/Foul, which (even after the recent parade to the line by Indiana) is fully 20% lower than the conference average. This, I suspect, is a bad thing, though I haven't found the numbers to prove it yet. As I ranted in the second Wisconsin post-game thread, the best fouls prevent easy buckets - dunks and layups. The worst are offensive fouls that turn the ball over but, defensively speaking, it's non-shooting fouls, which speed your team's journey to the bonus without creating defensive value. Committing a lot of fouls without sending people to the line, as MSU does, would seem to be indicative of bad defense: getting out of position, reaching for balls, not boxing out on rebounds, etc. Additionally, these numbers might indicate that, since we don't lack a willingness to foul, we may be giving up a lot of uncontested easy looks. I crunched the numbers and the good news is that there doesn't seem to be a significant correlation in the conference between opponents' eFG%, offensive efficiency or 2Pt% and how often they get sent to the line. For the conference season, MSU is still fairly good at defending the 2-point shot and somewhat more efficient than average overall. I thought perhaps the answer was that by not ending possessions with fouls, MSU gives their opponents more overall opportunities per possession to shoot and make field goals. Even that is not really the case, as the Spartans only give up a fairly average .85 Opp FGA per possession (Wisconsin is best at .79). I'm guessing this is due to strong defensive rebounding taking away the opportunities that the lack of shooting fouls creates.

So about all I can conclude is that our low Opp FTR masks a tendency to commit too many of the "wrong" kind of fouls, which in turn suggests some real defensive deficiencies. Judging by the increasing Opp eFG% we've been seeing in recent games (see this analysis), opponents may be beginning to exploit these deficiencies. And if our fouling tendencies reflected a more normal proportion of shooting to non-shooting fouls, the opposition would be finding another way to stay in the game, as Indiana clearly demonstrated.