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Lambeau Leap of Faith


February 28, 2010 3:26 AM

Analyzing the Offensive Line, Part II

For Part Three of this analysis of the offensive line, I will look at each individual. But no other unit has so much emphasis on how they work together as a unit, so I will continue in that vein for Part Two.

Before I get started on part two of this article, I want to give a list of all the team offensive line stats I compiled...


sck sck% hits hit% pass run ave -- neg% pwr 10+% 1st% TD% ps blk rn blk rating
Dolphins 34 6.2% 63 11.6% 579 509 4.4 37 7.3% 79% 10.4% 25.3% 4.3% 63.5% 92.1% 836.3
Patriots 18 3.0% 70 11.8% 610 466 4.1 35 7.5% 68% 10.7% 24.5% 4.1% 76.0% 72.6% 801.8
Bengals 29 5.0% 56 9.7% 606 505 4.1 50 9.9% 79% 10.9% 21.6% 1.8% 70.2% 73.5% 796.4
Saints 20 3.7% 52 9.6% 564 468 4.5 38 8.1% 67% 10.9% 24.6% 4.5% 75.7% 77.5% 790.0
Titans 15 3.2% 44 9.2% 491 499 5.2 50 10.0% 64% 13.0% 23.0% 3.8% 78.2% 75.1% 758.6
Jets 30 7.6% 53 13.5% 423 607 4.5 42 6.9% 73% 11.7% 21.7% 3.5% 56.0% 81.8% 733.0
Ravens 36 7.1% 72 14.1% 546 468 4.7 46 9.8% 72% 10.9% 24.6% 4.7% 57.6% 83.1% 703.6
Colts 13 2.2% 44 7.3% 614 366 3.5 43 11.7% 66% 10.1% 18.9% 4.4% 84.0% 48.7% 694.0
Falcons 27 4.7% 67 11.8% 597 451 4.2 32 7.1% 56% 10.2% 23.3% 3.3% 69.3% 61.1% 689.4
Texans 25 4.2% 92 15.5% 618 425 3.5 39 9.2% 64% 8.9% 22.1% 3.1% 67.6% 54.1% 648.0
Panthers 33 7.1% 62 13.3% 498 525 4.8 59 11.2% 66% 14.5% 23.4% 3.4% 58.3% 67.1% 642.4
Packers 51 9.2% 93 16.8% 604 438 4.3 32 7.3% 73% 9.6% 23.3% 4.6% 46.3% 82.4% 640.5
Cowboys 34 6.2% 78 14.2% 584 436 4.8 40 9.2% 57% 14.0% 25.2% 3.2% 61.1% 63.7% 634.6
Eagles 38 6.9% 67 12.1% 591 384 4.3 29 7.6% 64% 11.2% 22.7% 3.6% 60.4% 68.8% 621.1
Broncos 34 6.1% 62 11.1% 592 440 4.2 36 8.2% 56% 12.0% 21.6% 2.0% 64.5% 53.8% 618.6
Giants 32 5.9% 74 13.7% 574 443 4.1 43 9.7% 59% 11.7% 23.3% 3.2% 62.7% 55.6% 606.5
Vikings 34 6.1% 83 15.0% 587 467 4.1 51 10.9% 60% 12.0% 21.2% 4.1% 60.4% 52.7% 600.7
Jaguars 44 8.5% 126 24.3% 563 447 4.5 34 7.6% 69% 11.2% 25.5% 4.3% 41.8% 81.4% 599.3
Browns 30 6.8% 61 13.8% 473 498 4.2 41 8.2% 63% 11.4% 20.5% 2.0% 59.1% 60.5% 580.8
Cardinals 26 4.4% 93 15.7% 620 365 4.1 42 11.5% 50% 14.0% 26.6% 4.4% 66.8% 45.1% 578.9
Steelers 50 9.3% 78 14.6% 586 428 4.2 40 9.3% 70% 11.0% 22.4% 2.3% 48.1% 68.3% 574.6
Bucs 33 6.3% 95 18.1% 557 404 4 37 9.2% 65% 10.6% 19.8% 1.2% 56.7% 57.1% 546.3
Chiefs 45 8.4% 85 15.9% 580 438 4.4 53 12.1% 65% 11.2% 20.8% 1.8% 50.5% 57.4% 544.3
Bears 35 6.2% 79 14.0% 598 373 4 34 9.1% 56% 8.6% 16.4% 1.6% 61.1% 47.2% 541.3
Lions 43 7.4% 95 16.2% 628 409 4 54 13.2% 62% 11.0% 20.0% 2.2% 54.4% 46.8% 533.0
Seahawks 41 6.7% 91 14.9% 650 395 4 45 11.4% 48% 9.9% 20.3% 1.8% 58.1% 37.4% 525.4
49ers 40 7.6% 84 15.9% 567 371 4.3 40 10.8% 66% 13.2% 20.8% 3.2% 53.7% 59.4% 524.7
Chargers 26 5.0% 53 10.2% 545 427 3.3 39 9.1% 39% 7.5% 18.7% 4.0% 69.7% 29.7% 506.8
Raiders 49 10.1% 97 20.0% 534 410 4.1 31 7.6% 73% 10.2% 19.8% 1.7% 39.6% 70.8% 501.8
Rams 44 8.1% 98 18.0% 587 411 4.3 40 9.7% 57% 12.9% 19.2% 1.0% 49.5% 48.2% 488.9
Washington 46 8.6% 97 18.2% 579 391 3.9 29 7.4% 59% 9.2% 18.4% 2.0% 47.3% 54.0% 485.0
Bills 46 10.4% 103 23.4% 487 424 4.4 37 8.7% 48% 12.3% 19.1% 1.4% 34.9% 42.7% 351.0

After some deliberation, I came up with a formula to disseminate all the offensive line statistics into one composite rating. To get there, I first had to determine pass and run blocking proficiency.

For passing, sacks yielded deserve much more weight than quarterback hits, but the hits do matter--the more punishment signal-callers take, the less effective they are, and the more likely they will get hurt. And while NFL.com does not track quarterback pressures, the number of hits is a good indication of pressure the line gives up that does not result in a sack.

The formula I settled on to rate pass blocking was this: 1 -- (sack percentage x 4 + hit percentage). Originally, I only weighted sacks twice as much as hits, but frankly, the Packers offensive line ranked too highly when I did that--barely in the bottom third in pass blocking.

Thus, I made the decision to double the impact of sack percentage. While this still left the Packers with the same 29th-place ranking and left the average NFL pass blocking numbers significantly lower than the run blocking averages, it did increase the gap between Green Bay and the better teams, appropriate given these facts:

  1. No offensive line gave up as many sacks (51).
  2. Only three teams gave up a higher ratio of sacks per pass attempt (five had a worse hit percentage).
  3. After yielding 32 sacks in the first eight games, the line did improve, giving up just 19 in the second half of the season, or 2.2 per game. But that was still better than only 10 teams, and only the Philadelphia Eagles gave up even that many on the whole season and still made the playoffs.

Run blocking was a little more involved because of all the factors at play. The base statistic is obviously average yards per carry, but there are a lot of variables to this.

Power percentage is the percentage of third or fourth down and short (defined as one or two yards) in which a run resulted in a first down or touchdown. However, NFL.com tracks these as separate statistics for runs to the left, center, and right, and I do not have the ratio of runs going to each location--the best I could do was average the figures.

That stat makes touchdown and first down percentage less important, since those vital results are already a component of the less precise statistic. The greater accuracy of those stats helps to balance the power percentage's lesser precision while still giving weight to vital statistics like scores and moving the chains. Thus, I have factored all three stats into rating.

Finally, carries of 10 or more yards are more of an indication of an explosive running back than a great offensive line, so that actually is a countervailing statistic to average yards per carry. Meanwhile a lack of negative carries is more on the line than the back, but it is a negative statistic; both must be worked in as negatives to line strength.

To make the ratio close to the range of passing, I had to cut yards per carry (which average just over four) by 75%, leaving me with the following formula for run blocking: .25 x average/carry x (power% + TD% + first down % -- 2 x neg. carry % -- 10+yd carry %).

Originally, I had not doubled the negative carry percentage, but I feel that they are almost exclusively on the line (few backs get yards when hit behind the line), so I wanted more emphasis on that statistic. Moreover, it brought the average run blocking rating to within two percent of pass blocking.

However, only the New York Jets, Carolina Panthers, Tennessee Titans, and Cleveland Browns ran the ball more often than they passed it. Thus, for most teams, pass blocking is more important.

This is simple enough to factor in with a simple algebraic equation: if x = pass block rating and y = run block rating, and a team passes 60 percent of the time, the formula is (.6x + .4y) / 2--i.e. Pass blocking proficiency x pass frequency + run blocking proficiency x run frequency = overall line rating.

You can see based on these numbers that the Packers line, because it was ranked third in run blocking, ranked 12th overall. However, as I like to say (both in my analysis on websites and in my job, which involves a lot of number crunching), stats do not exist in a vacuum.

If a team has a great run blocking rating but a Pro Bowl running back, that has to take their line down a notch (cough*Vikings*cough). The Packers did not have a Pro Bowl back, but he was very close. In the end, that would count very little against the Packers.

As far as the pass blocking, the mobility of Rodgers (tops in the league) probably helped the line's stats barely more than his tendency to hold the ball (arguably worst in the league) hurt them.

The final variable is strength of opposition. The Packers played some very weak defensive lines: the Browns, Buccaneers, Rams, Seahawks, and Lions twice. But we also faced some great defensive lines: the Ravens, Steelers, Cowboys, Bengals, and Vikings twice. Again, this seems pretty even, although I will say the Ravens and Steelers were at less than 100 percent.

In other words, our 12th-ranked line according to composite stats should certainly be taken down a little by Ryan Grant's status as an almost-elite back (although our other backs left something to be desired), and maybe a bit more by both Rodgers' talent and the strength of competition.

That still makes them an average line overall--not what you would expect if you focus just on sacks yielded.

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