After signing a record-breaking deal that made him the highest-paid defensive player in NFL history, Khalil Mack went out and proved he was worth every penny. The Bears’ world-conquering pass rusher was simply unblockable — no matter how many poor souls opponents threw in his path — and his 12.5 sacks helped transform Chicago’s defense into the league’s best.

Mack’s cap hit for the 2018 season was a reasonable $13.8 million. That figure will jump to $22.3 million in 2019 — a number the Bears are more than happy to pay after Mack’s first season in Chicago. After that debut, I’m sure you could find plenty of Bears fans (and even members of the front office) who would tell you that Mack is worth any price you could name. But that’s obviously not true. In a league with a hard salary cap, there is a certain price point where, no matter how well Mack plays, he can no longer be considered an asset.

What is that price point? When does a player’s salary start to outweigh his contribution to the team? And what kind of effect can that have on a team’s ability to build its roster? Those questions have been rattling around my head since Mack signed his deal, which came shortly after Aaron Donald, a similarly dominant and generously compensated player, signed a massive deal of his own. The goal of this series, which we’re calling NFL Moneyball, is to attempt to provide (at least partial) answers to those questions.

I will not only seek to determine the true value of every NFL player, as dictated by the market for players, but also the most efficient way to build a roster. To do that, I’ve developed a metric based on two factors: A player’s production (based on his Pro Football Focus grade and snap count) and how much the league is paying for that production on average. I’ll call this stat Value Above Market Price — or VAMP.

Value Above Market Price, explained The goal of Value Above Market Price (VAMP) is to measure how much a player is being paid for his production by a team compared to the league-wide market rate for his position. A player’s VAMP is based on his production and cap hit in a given season compared to league averages. To calculate a player’s “production score,” I simply multiplied his Pro Football Focus grade by the number of snaps he played. Let’s use Patrick Mahomes as an example. Mahomes scored a PFF grade of 92.9 and played 1,165 snaps in 2018. So his “production score” was 108,228. Then I had to figure how much the league was paying for each point in that production score, and I did so for each position. So for quarterbacks, I added up every QB’s cap hit and divided it by the total “production score” of all QBs. That told us that in 2018, NFL teams paid $203.16 for every production point. (More on that later.) Using that number, I can determine how much Mahomes’ production was worth based on the market price for quarterbacks. We’ll call that number his “Real Market Value”… Finally, to get Mahomes’ VAMP, I just subtract his cap hit from his Real Market Value… Essentially, Mahomes provided the Chiefs with an additional $18.2 million in production. He was the MVP in more ways than one.

Figuring out how much players at each position were being paid for their production unlocked new insights about which positions executives around the league value most. It does not come as a shock that quarterback leads the pack by a wide margin, followed by the two positions tasked with harassing quarterbacks…

RK POSITION MARKET PRICE / PRODUCTION PT. 1 Quarterback $203.16 2 Edge rusher $113.28 3 Interior def. line $87.00 4 Wide receiver $85.82 5 Offensive tackle $79.73 6 Tight end $74.74 7 Center $72.75 8 Cornerback $72.57 9 Linebacker $68.19 10 Offensive guard $64.67 11 Running back $61.64 12 Safety $49.84

This chart is telling us that for every “production point” produced by an edge rusher, that player makes $113.28. Using that number, I can figure out how much Mack’s production during the 2018 season was worth based on the market. PFF gave Mack a grade of 90.7. Multiply that by the number of snaps he played, 819, and you get a “production score” of 74,283.

If the market pays edge rushers $113.28 for each point of production, Mack’s contributions to the Bears in 2018 would carry a value of $8.4 million. That’s nowhere close to the $13.8 million he actually counted against the cap.

This doesn’t mean that Mack is necessarily overpaid. It simply means the Bears paid a $5.4 million premium to have him on the roster. That’s not necessarily a bad thing considering the importance of pressuring the quarterback in today’s NFL. If you’re going to splurge on a position, make sure it’s one of the important ones.

While teams should certainly do everything in their power to add blue-chip talent to the roster, VAMP shows that finding bargains can be just as important as adding stars. Those bargains allow teams to pay their stars while maintaining the depth to remain successful throughout a grueling NFL season.

The best example of this is the Legion of Boom Seahawks, who dominated the league for a few years while their best players — Richard Sherman, Earl Thomas, Russell Wilson, etc. — were still playing on their rookie deals and providing surplus value. That allowed Seattle to go out and add veterans like Michael Bennett, Cliff Avril and Percy Harvin. Once the Shermans and Wilsons got paid and were no longer providing that surplus value, the overall quality of the roster took a big step back even if those star players had improved their individual games. Wilson, for instance, is now a far better quarterback than he was in 2013, but that inferior version of him (making under $1 million per season) was a far bigger asset to the franchise compared to now. I’ll use VAMP to show that is the case.

So which teams are currently getting the most out of their salary cap dollars? After determining every NFL player’s VAMP, I averaged those numbers out for players on each team. Let’s use the Chiefs as an example. Patrick Mahomes had the highest VAMP at $18.2 million, and Justin Houston had the lowest at -$12.4 million. I averaged every Chiefs player who played enough snaps to qualify for PFF’s rankings and came away with a final number of $352,743 — so, on average, the Chiefs got $352,743 more production from their players than they paid for.

Combining a team’s average VAMP with the amount of dead money on their books in 2018 allowed us to rank teams based on how efficiently they utilized their cap space last season, and we found that the best teams in the league were those that did the best job of spending their money wisely. You’re going to be SHOCKED when you see which team finished on top.

Just kidding, it’s the Patriots…

RK TEAM AVG. VAMP AVG. DEAD $ TOTAL 1 NE* $997,073 $208,073 $789,000 2 IND* $908,910 $241,570 $667,340 3 DAL* $1,232,667 $616,710 $615,957 4 PHI* $736,282 $281,273 $455,009 5 KC* $782,530 $429,787 $352,743 6 LAR* $642,891 $317,461 $325,430 7 PIT $327,053 $154,005 $173,048 8 HOU* $462,485 $292,285 $170,200 9 NO* $585,826 $429,775 $156,051 10 CHI* $375,920 $291,344 $84,576 11 DET $476,783 $464,775 $11,844 12 CLE $479,700 $489,090 ($9,380) 13 ATL $115,132 $173,073 ($57,941) 14 BAL* $185,268 $275,643 ($90,375) 15 SEA* $351,598 $516,974 ($165,376) 16 LAC* $117,914 $289,954 ($172,040) 17 NYJ $77,405 $490,467 ($413,062) 18 TEN ($366,970) $249,062 ($616,032) 19 NYG $178,783 $828,547 ($649,764) 20 GB ($471,430) $282,688 ($754,118) 21 MIA ($438,431) $379,152 ($817,583) 22 DEN ($337,807) $509,073 ($846,880) 23 BUF $370,816 $1,327,231 ($956,415) 24 CAR ($721,240) $237,523 ($958,763) 25 TB ($752,472) $210,623 ($963,095) 26 CIN ($802,389) $172,211 ($974,600) 27 OAK ($460,141) $547,062 ($1,007,203) 28 WSH ($783,623) $275,599 ($1,059,222) 29 SF ($860,085) $429,071 ($1,289,156) 30 MIN ($1,206,281) $134,154 ($1,340,435) 31 ARI ($772,384) $758,992 ($1,531,376) 32 JAX ($1,550,359) $392,692 ($1,943,051)

(Asterisk indicates playoff team.)

Nine of the top-10 teams made the playoffs. The Steelers — who might be the league’s biggest dumpster fire right now — were the one team that didn’t. Unfortunately, VAMP does not take team chemistry into account.

No team outside of the top half of the league made the postseason. The Jaguars and Vikings are interesting case studies. Both teams are loaded with star talent, but by spending so much cap space on those stars, they were unable to build up the rest of the roster. And that really became a problem when those highly-paid stars did not perform at a high level (or were dealing with injuries), which was the case in Jacksonville and Minnesota.

We know spending money efficiently is important. But how important is it? I ran a regression analysis to try to figure that out and found that there is a very strong relationship between spending efficiency and a team’s point differential.

Spending efficiency matters This may give you flashbacks to your stats class, but here’s some proof of how well VAMP correlates to winning football games (you can move ahead if you’re OK skipping the math): The correlation coefficient for these two measures was a very strong .74. The correlation of determination — in other words, what percentage of a team’s point differential is determined by their spending efficiency — was a whopping .50 or 50%. Some context: For the 2018 season, the correlation coefficient for total yards gained and point differential is .70 and the correlation of determination is .474 or 47.4%. The regression numbers for our “production score” metric and a team’s point differential are not significantly higher than those comparing VAMP and point differential. The correlation coefficient is .77 and the correlation of determination is .579 or 57.9%. In other words, production is only slightly more important than the price being paid for that production compared to the market.

Like all metrics, VAMP is nowhere near perfect. There are plenty of weaknesses, which I’ll acknowledge. The biggest might be its reliance on PFF grades to evaluate a player’s production. They are, of course, highly subjective and I certainly do not agree with all of their evaluations. Jalen Ramsey, for instance, was given a 72.8 grade for the 2018 season despite playing well while being asked to shadow the league’s best receivers every week without receiving much assistance. PFF grades are flawed (any metric measuring performance is going to be), but there isn’t another publicly available metric that we can use to compare performance across positions. And, for the most part, PFF does a good job of evaluating players.

Another major weakness — and one I’ll try to account for in subsequent posts — is the impact of players performing at a high level while on rookie deals that aren’t dictated by the open market. That certainly deflated the value of production across the board and makes it nearly impossible for a veteran player to produce at a level VAMP would consider a bargain. But that’s also, in some ways, an accurate reflection of how the league works now.

By focusing on the 2018 season, I am also working with a smaller sample size. I’ll continue to add information in subsequent seasons, which will give us more reliable data and allow us to draw conclusions with more confidence.

In the meantime, I’ll use VAMP to not only evaluate how teams are spending their money but also, and more importantly, to figure out how teams should be spending their money. Some other things VAMP will allow us to do over the next few weeks…

We’re just getting started, but we can already say one thing for sure: The teams that win in the NFL are those that get star production without paying the market rate for it.

This is NFL Moneyball.