Saturday, November 14, 2009

NFL Referee Statistics Before Week 10 (through Week 9, 11/9/09)

More data, but saving time by not going through all the categories Post a comment if you'd like a focus on any of the categories.

Here are NFL referee statistics to use in week 10 (use it for games starting November 12, 2009 because it includes data through week 9, games through November 9, 2009). This does not include the Thursday game on November 12.

I've been looking at over/under rates for correlations. Initial analysis -- no clear correlation for every season to the very next season but looking into potential correlations over a broader time period and by comparing the first half and the second half of the same season.

This is current as of November 11, 2009.

Home Team Win Rate
(the much-watched rate that home teams win for particular referees) These are unadjusted numbers and I have not seen a correlation from season to season, so this might not be correlated to specific referees. But we can track it anyway...
  • Highest: Mike Carey and Scott Green (75%); Bill Leavy, Terry McAulay, and Jeff Triplette (71%)
  • Lowest: Don Carey (25%); Ed Hochuli and Carl Cheffers (38%)
Total Points (adjusted and unadjusted). Unadjusted are raw total points. Adjusted compares the total points to the over/under line for the game.
  • Highest: Mike Carey (54.5, +10.1); John Parry (51.3, +9.6); Gene Steratore (49.1, +9.5)
  • Lowest: Jerome Boger (32.6, -10.1); Bill Leavy (37.1, -4.5); Walt Anderson (37.3, -6.6)
So Bill Leavy has lower scoring games but when you account for the over/under line, Walt Anderson averages lower than expected total points per game. But if you look for over/under rate, as opposed to averages over the season, the referees who more often have the "under" are Bill Leavy, Tony Corrente, and Walt Anderson (29%) with Jerome Boger and Peter Morelli right behind at (31%). On the high side, the top three in average total points are grouped at the top in over/under rate at 86-88%.

Data Dump of Selected Statistics -- ok, a short table of selected statistics, copy this into a spreadsheet and you can sort to your heart's content. Post a comment if you find certain details or details interesting. Or if you find interesting trends in your analysis!

Referee (sorted by last name), Total accepted penalties per game, Total penalty yards per game, Average penalty yards per penalty, Total points per game, Home team win rate.
Walt Anderson, 14.1, 126, 8.9, 37.3, 43%
Jerome Boger, 14.3, 107, 7.5, 32.6, 50%
Don Carey, 11.3, 89, 7.9, 42.3, 25%
Mike Carey, 11.1, 95, 8.6, 54.5, 75%
Carl Cheffers, 10.9, 91, 8.4, 45.6, 38%
Walt Coleman, 13.5, 104, 7.7, 44.4, 50%
Tony Corrente, 11.7, 94, 8.0, 39.9, 57%
Scott Green, 12.6, 106, 8.4, 45.3, 75%
Ed Hochuli, 13.8, 117, 8.5, 47.3, 38%
Bill Leavy, 11.1, 87, 7.8, 37.1, 71%
Terry McAulay, 11.6, 95, 8.2, 39.7, 71%
Peter Morelli, 10.9, 93, 8.6, 41.5, 63%
John Parry, 13.0, 105, 8.1, 51.3, 57%
Alberto Riveron, 10.6, 90, 8.5, 46.8, 63%
Gene Steratore, 10.0, 78, 7.8, 49.1, 57%
Jeff Triplette, 12.4, 98, 7.9, 47.3, 71%
Ron Winter, 14.6, 117, 8.0, 44.6, 63%

Sunday, November 01, 2009

Over/Under and Home-Team Referee Statistics from 2008 to 2009

Let's take a closer look at the over/under records for each referee who worked in the 2008 season and is now working in the 2009 NFL season.

We've charted out the over/under record for each referee in 2008 and 2009. Let's see if there is a correlation between how each one ranked in 2008 and how each one ranked in 2009 after the first 7 games of the season. There would be a strong correlation, for example, if the rankings in 2008 was the same as the ranking in 2009 (whoever had the best record for the over in 2008 also had the best record for the over in 2009).

However, the over/under correlation between 2008 and 2009 (after 7 games) is -0.213. That is a negative correlation, suggesting that if a referee had a great record for the over in 2008, the referee had a bad record for the over in 2009. That suggests perhaps the over/under is not so referee specific.

Next, we ran the same analysis in comparing the 2008 record for each referee and the 2009 record after 7 games if you always went with the home team when taking a position against the point spread (regardless of whether the home team was favored or the underdog).

The correlation for home team (against the spread) is even worse: -0.425. Maybe using this limited data, it is not suggesting that a particular referee is better for home teams across seasons against the spread.

To give you an idea how bad that correlation figure is, the figures between 2008 and 2009 so far are much higher for: total accepted penalties (0.574) and total accepted penalty yards (0.396).

Here are some examples on the over/under issue:
at the top:
Carl Cheffers: Over-2008 (73%) and Over-2009 so far (50%)
Bill Leavy: Over-2008 (67%) and Over-2009 so far (only 17%)

at the bottom:
Gene Steratore: Over-2008 (40%) and Over-2009 so far (a huge 100%)
Scott Green: Over-2008 (27%) and Over-2009 so far (57%)

Here are some examples on the home team against the spread:
at the top:
Alberto Riveron: Home Team ATS 2008 (63%) and Home Team ATS 2009 so far (50%)
Jerome Boger: 2008 (60%) and 2009 so far (only 14%)

at the bottom:
Scott Green: 2008 (33%) and 2009 so far (a huge 71%)
Gene Steratore: 2008 (33%) and 2009 so far (67%)
Ed Hochuli: 2008 (31%) and 2009 so far (33%)

Let's check in on this later in the season. If we see interesting correlation figures for other ways to analyze referees, we can post on it again on the blog.