Dr LIC's Krazy SyEnce Korner Pt. ???
A brief one for today, folks. For all of you academically inclined folks, SSRN is a wonderful repository of working papers, chapters in pdf form, and things that you would otherwise have to pay for. In my journeys through the site I have come across some great stuff on the social science of sports. The one that caught my eye most recently is a working paper entitled:
Sub-Perfect Game: Profitable Biases of NBA Referees
Available for download here. Economists Joseph Price (of Dave Berri collaboration and the study on racial bias amongst referees fame), Marc Remer, and Daniel F. Stone looked at over 28,000 quarters of NBA basketball from 2002-2008 using play-by-play data from ESPN.com to test (and confirm) the following hypotheses:
H1. The refs make calls that favor home teams
H2.The refs favor teams losing during games
H3. The refs favor teams losing in a playoff series.
Worse yet, the rationale for these biases is that each of them directly contributes to league revenue. As Price et al state, the "home bias" keeps the home team winning and therefore keeps home fans coming back and willing to pay more for tickets. The bias toward favoring the losing team keeps the game close--the authors refer to this as the "close bias"--and keeps fans watching on TV, perhaps also increasing interest in the game. And the "playoff bias" noted in hypothesis 3 keeps playoff series going longer, contributing to more TV revenue.
Regarding H1, the home team on average tends to have a significantly lower number of "discretionary turnovers"--turnovers called by the discretion referees--but no demonstrably different number of non-discreationary turnover--turnovers caused by the players alone. In addition, the home team accrues significantly fewer shooting and non-shooting fouls.
Regarding H2, teams down by 10 points one quarter have far fewer referee-initiated turnovers the following quarter, but this pattern doesn't emerge for non-discretionary turnovers. Losing teams also commit fewer shooting fouls, though the shooting fouls finding is open to alternative explanations.
Regarding H3, results are murkier, but teams down 0-2, 0-3, 1-3, or 2-3 in a playoff series have far fewer discretionary turnovers and get more shooting fouls.
I should add that it pains me to write about this, as I feel like the NBA refs are the most unfairly maligned refs in all of sports. Donaghy aside, we constantly hear that the NBA refs have too much control over the outcome of the game--but I can't help but wonder, given all we've seen in the NFL, MLB, and the World Cup fiascoes that the NBA refs are unfairly picked on. Zzzzzzz.
The authors point to a few potential causes of these biases all of which are very likely. The big question that remains for me, though, is how conscious are referees of these biases? Humor me and post your thoughts on this question and other proposed causes of the biases below.