Friday, May 16, 2008

Lakers-Jazz and homecourt advantage

I commented on this post over at a Utah Jazz blog earlier today which touched on the always contentious issue of refereeing favoring the home team. It was originally supposed to be a brief comment, but it grew as I was writing it. I guess I just tend to be verbose... Anyway, since it ended up being more of a post than a comment, I decided I'd also post it here (with a few minor modifications).
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Assuming I’m reading the tables correctly (always a big assumption!), the link to basketball-reference shows that the Jazz’s opponents get 23.1 fouls called against them on the road (i.e., in SLC) and 23.0 called against them at home—in other words, no difference. The Jazz, on the other hand, get called for 24.8 fouls on the road and 23.3 fouls at home. That seems to indicate that either the refs do let the Jazz get away with a little more contact at home (1.5 fouls worth) or the Jazz simply move their feet better at home. In either case, the Jazz’s opponents do not seem to benefit from being at home in the same way.

More interesting to me is where on the court the fouls seem to occur. When the Jazz are at home, their opponents shoot 27.9 free throw attempts. When the Jazz are on the road, their opponents shoot 32.3 free throw attempts. That’s five additional free throw attempts, but only 1.5 additional fouls (from which I would expect 3 additional free throw attempts at most). So not only do the Jazz get called for less fouls at home (or more on the road, whichever way you prefer to look at it), but they also seem to commit those fouls further away from the basket (i.e. not in the act of shooting). A more energized, aggressive team (the way a team often plays at home) could certainly explain this difference, but I found it interesting.

So the Jazz seem to get some homecourt advantage related to the reffing (or at least the fouls called), but what about the Lakers?

Basketball-reference shows that the Lakers’ opponents get 23.3 fouls called against them on the road (i.e., in LA) and 21.8 called against them at home. The Lakers, on the other hand, get called for 20.6 fouls on the road and 20.7 fouls at home—in other words no difference. That seems to indicate that the refs do not let the Lakers get away with more contact at home. However, it does seem to indicate that the refs let the Lakers’ opponents get away with less contact in LA than at home (1.5 fouls worth). The Lakers’ opponents do not seem to benefit from being at home in the same way.

In terms of where the fouls are called, the Lakers shoot 29.2 free throw attempts at home and 26.1 free throw attempts on the road. This seems perfectly consistent with getting 1.5 additional fouls called against their opponents at home. The Lakers’ opponents shoot 24.3 free throw attempts in LA and 24.4 free throw attempts at home, again consistent with the number of fouls called. Now I’m even more curious about what changes in how the Jazz play defense at home vs. on the road.

Long story short: Both the Jazz and Lakers appear to benefit from the refs’ calls at home, but they benefit in very different ways. The Jazz appear to benefit because they are called differently in SLC. The Lakers appear to benefit because their opponents are called diffently in LA.

It would be interesting to know whether all so-called “physical” teams benefit in the same way as the Jazz while all so-called “finesse” teams benefit in the same way as the Lakers. Unfortunately, I'm too lazy to go through the whole league sorting teams into these categories.

Anyone else want to do it?