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19 Jul 2010
by Bill Barnwell
In the article that introduces our plus-minus statistic for receiving in Football Outsiders Almanac 2010, I mention that I'll be publishing a scaled plus-minus figure on the website. This is that article.
For those who haven't read the book yet, here's a quick explanation. The plus-minus figure we introduced in these articles is included in the player comment tables for each wide receiver and tight end in the FOA player comments. We didn't have room in the running back tables, but the top ten and bottom ten running backs are listed in the appendix.
The figures provided are relative to that player's target total, not to a league-wide scale. That makes sense in the context of looking at an individual player, but it makes comparing different players with dramatically disparate usage patterns tricky. A guy with a plus-minus of -5.0 catches on 130 targets didn't have a great year, but he did far better than a player who accrued the same -5.0 plus-minus on 55 targets. Had that second player received the same 130 targets and continued to catch passes at a similarly poor level, he would have ended up with a plus-minus of -11.8 catches.
With that in mind, I wanted to offer plus-minus as a scaled metric, commenting on notable performances. I'll be taking all the plus-minus figures from the past few seasons and scaling them to a rate of 150 targets.
For players with a small sample of passes, this naturally produces an absurdly high figure. I sincerely doubt that Dan Kreider -- who caught none of the four "catchable" passes thrown to him in 2008 -- would produce a plus-minus of -120.9 if he was actually thrown 150 passes. (This would either be a terrible offense, or a season's worth of third-and-longs for the Carolina Panthers.) Therefore, I'll limit the discussion to players who only had 30 or more relevant targets in the given season.
Using raw plus-minus, last year's leader was unsurprisingly a player who gets a large number of targets: Indianapolis' Reggie Wayne, who had a plus-minus of 16.9 on 134 targets. (Remember, this target total differs from the one on his player page because we eliminate a group of uncatchable targets.) Because Wayne only gets a slight bump from our scaling, though, Wayne's scaled plus-minus is 18.9; still superb, but only good for sixth in the league in 2009.
So who led the league in scaled plus-minus? One of the league's most surprising performers in 2009:
There are several major 2009 surprises in that group, notably league leader Robert Meachem. A 70 percent catch rate is extremely likely to regress towards the mean, even for a possession receiver, but 30 percent of the passes thrown to Meachem last year were bombs. Given his target package, his expected catch rate was something like 56 percent; even Drew Brees can't make up that difference.
Behind him is one of this year's Top 25 Prospects, Jacoby Jones, and two spots behind him is fellow Texans wideout Kevin Walter. Naturally, they get a bump through playing across from elite wide receiver Andre Johnson, whose plus-minus per 150 targets (4.1) isn't particularly impressive. Interestingly enough, while you might expect that bump to be consistent, this method of analyzing catch rates doesn't always suggest that to be the case. In 2006, it was markedly similar; Johnson had a scaled plus-minus of 2.6 while Eric Moulds was among the league leaders at 17.0. A year later, Johnson was at 17.8, twice the figure of anyone else on the team. A year ago, all four qualifying targets -- Owen Daniels, Walter, Johnson, and Steve Slaton -- had scaled plus-minus figures between 10.7 and 14.2. That's three totally different statistical signatures in three years.
What happened to players with excellent scaled plus-minus figures from a year ago, though? Were they able to maintain their impressive rates? The evidence is inconclusive. Of the top ten players from a year ago, two (Ike Hilliard and David Martin) did not catch a single pass, and two more (Thomas Jones and Jason Hill) did not get 30 targets. The other six were a mixed bag; league leader Malcom Floyd (a whopping scaled plus-minus of 35.1) was down to 10.7 last season. Steve Breaston maintained his rate, but players like Josh Reed (21.3 to -5.7) and Devery Henderson (17.9 to 4.9) exhibited serious dropoffs, and even those blessed with the magic of Favre declined: Visanthe Shiancoe went from 17.3 to 8.6, while Chester Taylor's figure dropped from 16.4 to -2.6. The year-to-year correlation for receivers with 30+ targets in consecutive seasons is .22, which isn't very strong at all.
Floyd's figure is the highest over the four-year stretch. There are some other interesting players in the top ten that we'll get to in a later article.
On the flip side, the eternal battle of stone hands between Ashley Lelie and Darrius Heyward-Bey that we discuss in DHB's player comment really comes into focus with these scaled figures. In this analysis, Lelie finishes with the worst figure of the past four seasons, at a gruesome -43.9; Heyward-Bey is just behind, at -42.7. The rest of the top ten for 2009:
The only player in that group who was part of a passing game you wouldn't be embarrassed to show your family is Roy Williams. That's no surprise on all counts. I subjectively thought Louis Murphy played reasonably well for a player in the Raiders' offense last year, but he had a pretty gruesome plus-minus figure.
Most of the players in the bottom ten from a year ago dropped off of league radar. Only two -- Braylon Edwards and Adrian Peterson -- had 30 or more targets in 2009. The 11th-ranked player in 2008 was Benjamin Watson, who you'll note was in the top ten in 2009. In 2007, only three of the top ten made it to 30 targets; that suggests some impending attrition for borderline veterans like Jerramy Stevens, Bryant Johnson, and Randy McMichael.
Of course, there's still much more work to be done. Much like Dean Oliver did for his sport in Basketball On Paper, we need to analyze and chart the relationship between efficiency and usage. Next, though, I'll be tackling another problem: how well a player caught passes compared to the rest of his teammates.
19 comments, Last at 22 Jul 2010, 9:19pm by guy