Saturday, October 20, 2007

NFL Referee Statistics 2007 (Week Six)

NFL referee statistics for the 2007 season -- this report is after week six, through games of Monday, October 15:

Likely correlation between referees who calls lots of penalties and the rate that the home team wins the game. There is an even stronger correlation than usual after six weeks of how many accepted penalties there are for the referee and the rate that the home team wins the game. The correlation is a striking 0.496 right now. As an example, the three referees with the highest number of penalties per game have home winning rates of 75, 75, and 67%. While the four referees with the lowest number of penalties per game have home winning rates of only 50, 40, 20, and 0%

Possible relationship between the referee who calls the game and how many penalties there are and the rate the home team wins the game. One way to check on whether the referee has a relationship to how many penalties are called or the rate the home team wins is to compare those statistics in 2007 with the same statistics for those referees in 2006. Then to see if there is some correlation between the 2006 rates and the 2007 rates for those referees. After 6 weeks, a comparison of those referees with stats in 2006 and 2007 suggests there is a relation between the ref and penalties called or home team win-rate. The correlation for penalties called is a positive 0.103 while the correlation for the home team's win rate is a fairly large positive 0.343!

Referees by penalties accepted per game:
The refs with the highest penalties accepted per game (with the home win-rate) are:
Walt Anderson (15.3, 75%)
Ron Winter (13.8, 75%)
Terry McAulay (13.7, 67%)
Bill Leavy (13.6, 40%)
(and the bottom of the list is)
David Coleman (9, 0%)
Jeff Triplette (8.4, 20%)
Pete Morelli (8.2, 40%)
Gerald Austin (8.2, 50%)

Referees by home win-rate: if you believe the referee has some influence (perhaps an unintentional tendency) on whether the home team wins, then use this list. Here's the list, again with the penalties per game followed by the home team's win-rate.
Barry Anderson (10, 100%)
John Parry (13.2, 80%)
Tony Corrente (12.2, 80%)
Ed Hochuli (11.6, 80%)
(and at the bottom of the list)
Bill Leavy (13.6, 40%)
Pete Morelli (8.2, 40%)
Jeff Triplette (8.4, 20%)
David Coleman (9.0, 0%)

Let's set aside "Barry Anderson" and "David Coleman" who might have been typos by the NFL statistical team. We are taking stats from the official NFL web reports.

So, if you are rooting for the home team, hope you have John Parry, Tony Corrente, or Ed Hochuli. And be unhappy if you have Jeff Triplette, Pete Morelli, or Bill Leavy.

Here are all the referees as listed on the official NFL game reports on their web site. The numbers in parentheses are penalties per game, penalty yards per game, and the home win-rate:

Barry Anderson (10, 50, 100%)
Walt Anderson (15.3, 110, 75%)
Gerald Austin (8.2, 73, 50%)
Jerome Boger (11.8, 95, 75%)
Mike Carey (12, 92, 50%)
Bill Carollo (11, 80, 60%)
David Coleman (9, 84, 0%)
Walt Coleman (12.3, 85, 75%)
Tony Corrente (12.2, 95, 80%)
Scott Green (10, 74, 50%)
Ed Hochuli (11.6, 97, 80%)
Bill Leavy (13.6, 109, 40%)
Terry McAulay (13.7, 112, 67%)
Pete Morelli (8.2, 63, 40%)
Larry Nemmers (11.2, 103, 50%)
John Parry (13.2, 97, 80%)
Gene Steratore (12.8, 99, 50%)
Jeff Triplette (8.4, 60, 20%)
Ron Winter (13.8, 100, 75%)

Saturday, October 06, 2007

NFL Referees Week Four Report

Here's our report through four weeks of NFL games for the 2007 season. This includes games through Monday, October 1, 2007:

The rate that the home team wins might be realted to which referee is covering the game. We are seeing preliminary evidence that the rate the home team wins the game might possibly be realted to which ref is covering the game. But this evidence is extremely preliminary -- but something we will keep an eye on. If you compare the home team win rates in 2007 with the rates in 2006 for those refs who were working in both seasons, you will see a 0.187 positive correlation! This is initial evidence suggesting perhaps the rate the home team wins will depend a bit on the referee. But let me offer some comments on this -- the finding is extremely preliminary -- it is hard to rely on only four games for the 2007 trend. Also, even if we find out the rate is related to which ref you have, that does not mean that referees are intentionally trying to influence games. If that trend exists, it is quite likely that the referees have the same kinds of unconscious tendencies that every person has. Maybe some referees fight off the unconscious tendency better than others.

Home teams do better with referees who usually call more penalties. As with the 2006 season, the initial results of the 2007 season through week four also suggest that home teams do better with referees who call more penalties -- there is an 0.311 correlation between total penalties per game and the home team's win-rate.

Referees who call more penalties tend to call more against the visiting team. Through four weeks, the correlation between the penalties accepted per game and the percent of the penalties called against the visiting team is very positive at 0.503. Why? Not sure, maybe there is a certain batch of penalties that referees call without regard to which team is the visiting or home team (perhaps obvious false start penalties?), but maybe there is a grey area and referees who call more of those grey-area penalties have an unconscious tendency to call more of those against the visiting team. Just a theory -- post a comment if you have other theories.

Something to keep an eye on: after four weeks, a huge correlation suggesting referees that call the big penalties (large average yards per penalty) are good for visiting teams. The correlation is a huge 0.524 between a referee's average yards per penalty accepted and the visiting team's win-rate. What's going on there?

Turning to the referee rankings so far:

Penalties accepted per game: Bill Leavy (16), Terry McAulay (15.3), Gene Steratore (14.8) at the top and Gerald Austin (6.8), Pete Morelli (7.8), and Jeff Triplette (8.7) at the bottom.

Home team's winning percentage: Walt Anderson and Barry Anderson are at the top (100%) followed by Gene Steratore, John Parry, Ed Hochuli, and Gerald Austin (75%). AT the bottom, David Coleman (0%), Jeff Triplette (33%), then seven referees tied at 50%.