5 Stats That Might Mean Less Than You Think
We're living in the golden age of statistics for sports geeks. If you want to estimate how many wins Wilt Chamberlain accounted for in the 1963-1964 season, you can do that. If you want to know whether people with the initial K strike out more often, you can do that, too. Many number crunchers believe the old stats we grew up with aren't actually very helpful. Like these:
Because it's such a team sport, baseball is chock full of metrics that give, at best, an incomplete picture of a player's performance. Take Runs Batted In, still one of the chief offensive statistics. Sure, the all-time RBI list is a who's who of the best hitters—Hank Aaron, Babe Ruth and Barry Bonds are the top three—but critics have long argued that it's a poor way to judge how good an individual hitter is. In The Sabermetric Manifesto, David Grabiner wrote that RBIs are not "meaningless, only incomplete" because they don't measure a batter's full offensive production. Outside of a solo home run, the only way to record an RBI is to have someone on base ahead of you, so even if you put, say, Hank Aaron onto the Miami Marlins, there just wouldn't be many chances.
2. Pitcher Wins
But the RBI debate pales in comparison to some of baseball's long-hated pitching stats. When Felix Hernandez won the Cy Young award in 2010 despite recording just 13 wins (by contrast, last year's two winners each had 20 wins), it was hailed as a victory for the stat geeks. Among his achievements, Hernandez led the American League in ERA, quality starts, and fewest hits per nine innings, and was second in strikeouts, walks and hits per nine innings. In short, just about everything except for wins, which most saw as a reflection of the putrid Seattle Mariners team he pitched for. A great pitcher on a bad team might look unimpressive in the win column simply because his team doesn't score.
3. Points Per 48 Minutes
Of course, the statistical noise goes well beyond baseball. Take basketball, where minutes played is still an oft-tallied and much-discussed statistic, with estimates of what a player's contribution would be over a full 48-minute game. But as Hall of Famer Charles Barkley has said, the only reason to consider what somebody would have done in 48 minutes is because they weren't good enough to play all 48 in the first place.
4. Passer Rating
Even football—with its multi-million dollar fantasy business based entirely on statistics—has struggled to come up with a set of advanced metrics of its own. That's highlighted by the ultra-confusing quarterback passer rating, measured on a scale up to 158.3. Even the NFL has admitted the stat only rates passers, not total quarterbacks. QBR doesn't fully account for rushing plays, the offense the QB plays in, or his overall record, and the stats "do not reflect leadership, play-calling and other intangible factors," according to the NFL's own site. And while QBR has its defenders—Sports Illustrated's Kerry Byrne has pointed out that it does correlate closely with winning percentage—ESPN has worked to replace it with their Total QBR stat, which they say incorporates the context of each play to better account for the quarterback's contribution. But that has its own critics for being too confusing and for not weighing scores based on the situation.
5. Time of Possession
Even one of the most valued NFL stats—time of possession—is being challenged. The argument went that the team who had the ball the longest was dominating on offense and "controlling the ball." But that's given way recently to a number with even more bearing on the game: points scored. New Philadelphia Eagles coach Chip Kelly, who prides himself on his fast-paced offense, recently took aim at the traditional time of possession figures, saying it was really "how much time can the other team waste?"
"Most games, we lose the time of possession, but it's how many snaps do you face?," Kelly said. "And I think in both [preseason] games we've played, we've played more snaps than our other team."
Across all sports, there are traditional metrics that may not ultimately carry much value. Fans have questioned hockey's shots on goal numbers, pointing out that shots that don't go in still don't count for anything. People talk about serve speed in tennis, but that ultimately doesn't reflect how a player reacts or plays on the surface. Golf's "Driving Accuracy Percentage" is supposed to measure the number of hits that land on the fairway, but doesn't really measure how errant a shot is or how it impacts performance.
But with so much attention on slicing and dicing every shot of every game, there's a good chance that every questionable stat will be tweaked and refined and replaced with something else. That is, until something more advanced comes along to replace them.
Game Changers: Real. Sports. Data.
A recurring web series on sports and big data, featuring industry experts and social commentary. For more information, visit ibm.com/sports.