For the past few years, I have written a weekly in-season article for the New York Times’ football blog, The Fifth Down. We are teaming up again this year and below is an excerpt from some thoughts I had on the replacement refs:

It was an uneventful Week 1, in a good way, as the N.F.L. replacement referees did not steal much attention from the players on the field.

There were the usual complaints and borderline calls, including a flag thrown on a textbook block in the back by Green Bay on Randall Cobb’s touchdown return against San Francisco on Sunday. Instead, the referees picked up the flag, and the Packers’ score counted. In Arizona, an inexcusable gaffe allowed Seattle to have four timeouts as they frantically attempted to tie the game. But both the Cardinals and the 49ers won, muting any cries about the replacement officials.

It’s difficult to test whether the replacement referees were any different than the regular crews. Tests work best with objective data, and the performance of referees is inherently subjective. But we do have some numbers to go by.

Some have argued that the officiating crews let defensive backs play more physically than the regular officials have allowed in recent years, thinking that the replacements were loath to throw huge flags in key situations. But in that infamous final minute in Seattle, the referees flagged Arizona for defensive pass interference on two key plays. In fact, there were 29 defensive pass-interference penalties called by the referees in Week 1, the most during an opening week since at least 2000. Over the last 10 years, there have been 130 such penalties called during the opening weeks of N.F.L. seasons, or 13 per year.

Despite the subjective arguments, replacement officials called defensive pass interferences more than twice as frequently as the regular crews have done in Week 1. Maybe coaches were instructing their defensive backs to play more physically, hoping that the referees would be afraid to throw the flag. Regardless, the evidence in no way supported the idea that the replacements were letting defensive backs get away with more.

What about penalties over all? On average, over the last 10 years, 208 penalties have been called in Week 1. With the replacement referees over the last week, there were 206 penalties, in line with historical averages. Penalty yardage was slightly up, most likely as a result of more defensive pass interference calls, but that metric was also in line with norms.

You can read the full article, here.

Since then, Mike Kania, who refers to himself as the code junky for Pro-Football-Reference and the other Sports-Reference websites, sent me some additional data. The table below shows the number of each type of penalty called in week 1 of the 2011 season and week 1 of the 2012 season ^[1]I’m not sure why Mike and I have slightly different numbers on defensive pass interference penalties; it might be that 29 were called and 26 were enforced (i.e., 3 were declined), but I … Continue reading, along with how many penalty yards were associated with each penalty. In the far right three columns, I’ve shown the difference between the two seasons.

Penalty	2011 Count	2011 Yds	2011 Yd/Pen	2012 Count	2012 Yds	2012 Yd/Pen	Diff Count	Diff Yds	Diff Yd/Pen
False Start	41	206	5	40	196	4.9	1	10	0.1
Offensive Holding	37	354	9.6	42	402	9.6	-5	-48	0
Unnecessary Roughness	15	218	14.5	7	99	14.1	8	119	0.4
Delay of Game	13	65	5	12	60	5	1	5	0
Illegal Block Above the Waist	13	128	9.8	8	80	10	5	48	-0.2
Defensive Offside	11	55	5	14	70	5	-3	-15	0
Encroachment	10	49	4.9	3	15	5	7	34	-0.1
Defensive Pass Interference	8	83	10.4	26	321	12.3	-18	-238	-1.9
Neutral Zone Infraction	7	34	4.9	9	45	5	-2	-11	-0.1
Defensive Holding	6	30	5	5	25	5	1	5	0
Illegal Contact	6	29	4.8	1	5	5	5	24	-0.2
Unsportsmanlike Conduct	5	65	13	1	15	15	4	50	-2
Horse Collar Tackle	4	51	12.8	2	16	8	2	35	4.8
Illegal Formation	4	20	5	2	10	5	2	10	0
Ineligible Downfield Kick	4	20	5	1	5	5	3	15	0
Offensive Pass Interference	4	40	10	3	30	10	1	10	0
Roughing the Passer	4	56	14	8	112	14	-4	-56	0
Illegal Use of Hands	3	15	5	3	25	8.3	0	-10	-3.3
Offside on Free Kick	3	15	5	1	5	5	2	10	0
Defensive 12 On-field	2	10	5	1	5	5	1	5	0
Face Mask (15 Yards)	2	30	15	4	46	11.5	-2	-16	3.5
Illegal Shift	2	10	5	0	0	-	2	10	-
Intentional Grounding	2	30	15	1	12	12	1	18	3
Roughing the Kicker	2	16	8	0	0	-	2	16	-
Illegal Crackback	1	15	15	0	0	-	1	15	-
Illegal Substitution	1	5	5	3	15	5	-2	-10	0
Ineligible Downfield Pass	1	5	5	0	0	-	1	5	-
Personal Foul	1	15	15	4	60	15	-3	-45	0
Running Into the Kicker	1	5	5	0	0	-	1	5	-
Clipping	0	0	-	1	13	13	-1	-13	-
Fair Catch Interference	0	0	-	1	15	15	-1	-15	-
Illegal Motion	0	0	-	1	5	5	-1	-5	-
Interference with Opportunity to Catch	0	0	-	2	30	15	-2	-30	-

I’ll let the reader draw his or her own conclusions in the comments.