Slate - Why Doesn't Football have a Bill James? Football and statistics

n 1977, a boiler-room attendant named Bill James revolutionized baseball analysis with a self-published pamphlet called the Baseball Abstract, sweeping conventional wisdom aside with his radical reinterpretation of the statistical record. James' insights, since embraced by the front offices of the Oakland A's, the Boston Red Sox, and the Toronto Blue Jays, should have inspired the serious students of America's other national game, football, to overturn their status quo. But a quarter-century later, nobody has. Why?

For one thing, a football game is several orders of magnitude more complex than a baseball game. For another, nobody has yet determined what the most useful data to collect might be. And finally there's the problem of data points: The 16-game NFL season leaves less stuff to count than Major League Baseball's 162 games.


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By today's computing standards, Carter's data set was minuscule and his hardware archaic. To run the numbers, he reserved time on Northwestern's IBM 360 mainframe. Processing a half-season query would take 15 or 20 minutes—something today's desktop computers could do in nanoseconds. In one research project, Carter started with the subset of 2,852 first-down plays. For each play, he determined which team scored next and how many points they scored. By averaging the results, he was able to learn the "expected value" of having the ball at different spots on the field.

[Virgil] Carter deduced that the value is negative when the ball is inside a team's own 20-yard line—that is, that the team playing defense will likely score before the one playing offense. Carter and his professor Robert E. Machol co-authored a paper based on his findings, "Operations Research on Football," for a statistical journal. Carter's insight proved prescient: In the 1998 edition of the book The Hidden Game of Football, the statistically savvy authors ran a similar study and came to the same conclusion. The expected value is essentially linear, starting at -2 points at your own goal line, moving to +2 at midfield, and rising to +6 at the opponents' end zone.

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ust as there are difficulties associated with quantifying individual ability, there are similar problems with analyzing teams. In football, the scoreboard changes strategy far more often and to a greater degree than in baseball. Whereas a baseball team tries to get hits and score runs in essentially the same fashion no matter what the score, if a football team is down by two touchdowns in the second half, they'll often abandon half their offense and rely solely on the pass.

Jim Schwartz knows from experience why most conventional stats make no sense. When he was a coach with Baltimore in 1996, he says, the Ravens were No. 2 in the NFL in passing because they were always behind and desperately heaving the ball to catch up. Schwartz, now the defensive coordinator with the Tennessee Titans, studied econometrics at Georgetown University, then earned what he calls a "Ph.D. in footballology" as an assistant coach with the Cleveland Browns under Bill Belichick. Schwartz took the Jamesian initiative to suss out whether certain statistics correlated with winning and was surprised to learn, after studying five years of data, that fumbles were evenly distributed between winning and losing teams. Belichick was incredulous when Schwartz reported his finding. "He was like, 'Good teams don't fumble.' "

When reviewing game film, Schwartz uses a simple grading system: He gives a plus (positive impact), a minus (negative impact), or a zero (no impact) to each player on each play. "You take those and then you can push them into an equation," he says. "You basically have an 11-variable equation and the result is yards gained. Over the season, over 1,000 plays, you can isolate a variable." Schwartz hopes to use his data to make personnel decisions: If a minus play by a defensive lineman costs the team on average more yards than a minus play by a linebacker, then perhaps linemen should be more of a priority in the draft or free agency.

Lots of interesting applications. Read the full article here at Slate. (Which is one of my favorite reads online.)