Thursday, April 17, 2014

National Friday League: A Simple Look at Sacks Over the Years

Are sacks harder to come by in the NFL today? It's simple enough to look: pro-football-reference.com records data on pass attempts, sacks, and sack percentage going back to 1969. Let's take a look starting at the merger, and starting in '73 let's just skip through every 5th season. We'll look at the team average for pass attempts per game, league sack percentage, team average for sack totals, and the leading team's sack totals (I'll translate the latter two stats into sacks per game so we can compare 14 game and 16 game seasons). This is an imprecise look, but maybe we'll learn something (I can't do advanced metrics: I'm just looking at history to explore curiosity).

1970: 26.9 attempts per game, 8.2% sack rate
team average: 2.4 sacks per game  leader: Los Angeles 3.8 sacks per game

1971: 25.9 apg, 7.5% sack rate
team average: 2.1  leader: Denver 3.1

1972: 24.8 apg, 7.8% sack rate
team average: 2.1  leader: San Francisco 3.3

1973: 24.3 apg, 8.9% sack rate
team average: 2.4  leader: Washington 3.8

1978: 26.4 apg, 7.9% sack rate
team average: 2.3  leader: Dallas 3.6

1983: 31.4 apg, 8.0% sack rate
team average: 2.7  leader: St. Louis 3.7

1988: 31.5 apg, 6.8% sack rate
team average: 2.3  leader: Rams 3.5

1993: 32.2 apg, 6.8% sack rate
team average: 2.4  leader: Houston 3.3

1998: 32.3 apg, 7.2% sack rate
team average: 2.5  leader: New York Giants 3.4

2003: 32.2 apg, 6.2% sack rate
team average: 2.1  leader: Baltimore 2.9

2008: 32.3 apg, 5.9% sack rate
team average: 2.0 leader: Dallas 3.7

2013: 35.4 apg, 6.7% sack rate
team average: 2.5  leader: Carolina 3.8

I've only recorded every five years here, but I've checked the other years to see if there was anything fluky about these particular years. There really isn't: team averages in '13 were higher than in the previous three seasons (2.2, 2.2, 2.3, 2.3), and this list misses the high sack total seasons ('84 Bears' 4.5 sacks per game, the league average of 2.9 in '84, and 2.9 in '85), and the low point for sack totals  in the 16 game era ('94).

What do we learn? Well, this isn't the advanced metric to determine the relationship between changes in pass attempts and changes in sack rate on sack totals (though it's remarkable how steady the attempts and sack rate numbers are over the last 25 years). But basically, there isn't a whole lot of change in the league average team sack total, or in the team leader sack total total. Whether it's harder or easier to get sacks, the numbers are basically pretty steady and comparable. You can also look at the individual sack leaders year by year since 1982 to see there really are no giant changes up or down. In the 16 game era, it seems fair to compare individual players' sack totals with each other.

Kick Ass Link
I'm a secondary character in this remembrance of a person joining a fantasy football league (Sportzball). This is also hilarious: you'll have fun reading this.

2 comments:

  1. PV:

    This dovetails well with your recent post about who was the Vikings greatest defensive end - Eller or Allen. ETR and I had a bit of a back and forth on it and I mentioned that you had to account for the fact it's probably harder to get sacks today with West Coast offenses and short passing, blah, blah, blah then it was in Eller's day. But despite the fact teams are passing almost 10 more times per game than they did in 1973, the sack percentages haven't changed a whole lot, suggesting it's only slightly harder now to sack the QB than it was 40 years ago.

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    1. I guess what I'm saying is it makes Eller's accomplishments even more impressive and he's hands down the best DE the Vikings have ever had.

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