Commentary

Professor: Stats show something unusual happened in Clemens' career

Updated: February 10, 2008, 6:29 PM ET
By Lester Munson | ESPN.com

In addition to a war of words with George Mitchell and Brian McNamee, Roger Clemens now finds himself in a battle over numbers with four economics and statistics professors from the prestigious Wharton School of the University of Pennsylvania.

The argument began when Clemens and his crisis management team produced a 45-page report with 38 charts that used his pitching statistics to try to support his assertions that he never once used performance-enhancing drugs.

"If Clemens had not suggested that statistics showed his innocence, we would not have become involved in this," said Justin Wolfers, one of the professors at Wharton, a business school.

"What they said in their report is indefensible as a matter of statistics," Wolfers said. "The statistics do not point to innocence. We are not saying that the numbers show guilt, but we are saying that the statistics show that something unusual happened in Clemens' career as he entered his 30s."

In their report, first published Sunday in The New York Times, the four professors compared Clemens' career numbers to those of 31 other "durable pitchers" who started at least 10 games in at least 15 seasons and pitched at least 3,000 innings. They concluded Clemens' late-career success, coming during the period in which McNamee says he injected Clemens with human growth hormone, "raises some suspicion."

The professors do not claim to have found evidence of guilt, but their study shows there is "no statistical evidence that points to innocence," Wolfers said. "You cannot use his statistics to prove that he is innocent. It is not statistically possible. What they are doing is a good example of lying with statistics."

You cannot use his statistics to prove that he is innocent. It is not statistically possible. What they are doing is a good example of lying with statistics.

--Wharton professor Justin Wolfers

The Clemens war room was quick to react to the professors. Joe Householder, a public relations and crisis management expert hired by the Clemens team, attacked the professors' use of the word "suspicion," suggesting that "these statisticians are engaging in precisely the kind of insinuation with their words that they say cannot be proven by statistics."

The principal issue in the numbers battle is the group of pitchers studied. The Clemens report compared Clemens to three other pitchers who did well late in their careers: Curt Schilling, Randy Johnson and Nolan Ryan. The comparison, the Clemens team says, shows there is nothing unusual about Clemens' late-career success.

The professors, using 31 pitchers, concluded the arc of Clemens' career was "unusual," because his "performance declines as he enters his late 20s and improves into his mid-30s and 40s." The arc of numbers, the professors say, is "upside-down" when compared to those of other durable pitchers who "improve steadily early in their careers, peaking at around 30" before slowly declining into their 30s.

Speaking for the Clemens team, Householder disagreed. Clemens was not in decline in his 20s, Householder asserted. He offered some impressive numbers: Clemens was second in voting for the Cy Young at age 27, won it at age 28, and had ERAs below 3.00 between ages 27 and 30.

Clemens' representative also argued the pitcher's workout regimen and his late-career use of the split-finger fastball contributed to his success in his 30s and 40s.

Wolfers replied that "there are absolutely no statistics that support any conclusions about workouts or pitch selection in their report. The suggestions about workout and the split-finger pitch are rhetoric unsupported by a single statistic."

The professors are not done. They are completing a 15-page report that will be available in a few days and will be published in an academic journal on statistics. It will expand on the 800-word article that appeared in the Times, and it will go through Clemens's career using all available pitching statistics.

When it's over, the professors probably will win the battle of numbers. Their expertise is overwhelming, and they were not hired to reach any conclusion. But the battle proves the dictum President Ronald Reagan made famous in his debate with President Jimmy Carter: "Figures lie, and liars figure."

Lester Munson, a Chicago lawyer and journalist who reports on investigative and legal issues in the sports industry, is a senior writer for ESPN.com.