Rishel’s Research on Football Wagers Gets Play in Men's Health Magazine
Published on November 8, 2011
Update: Tracy Rishel’s research is recognized in Men’s Health magazine. Read the article.
When bookmakers set the over/under line for NFL games, they tend to give weight to the number of points a team scored in its last game. But that statistic is a poor predictor of the number of points that will be scored in the next game, according to one Susquehanna University faculty member.
“This may mean that bettors place too much emphasis on recent information,” says Tracy D. Rishel, associate professor of management at Susquehanna, who analyzed over/under lines and the results of more than 190 National Football League games played in 2010 and the effects of several variables used to set the betting line.
“We are able to explain about two-thirds of the variance in the over/under betting line for individual games with the variables we examined,” reports Rishel. “The data are very consistent across two years’ study, both in 2010 and in research we did earlier on the 2008 NFL season.”
The over/under line set by bookmakers is an attempt to predict the number of points to be scored by both teams in the next game. Bettors can choose the “over” if they think more points will be scored than the odds makers predict, or they can select the “under” if they think fewer points will be scored.
As expected, the researchers found that offense vs. defense matchups play significant roles in setting the over/under line. They play a lesser but still noticeable role in predicting scores.
“Matchups count,” notes Rishel. “Examination of yards gained on offense matched against yards surrendered on defense, was highly statistically significant in the placement of the betting line.”
Rishel and two economists from Randolph Macon College—C. Barry Pfitzner and Steven D. Lang—presented a paper on their results in October at the annual meeting of the Southeast Institute for Operations Research and Management Sciences in Myrtle Beach, S.C. Their study is titled “The Determinants of Scoring in 2010 NFL Games and the Over/Under Line.”
The work by Rishel, Pfitzner and Lang could serve as a caution for football bettors. “The line, as expected, is much easier to predict than the actual points scored,” says Rishel. “The outcomes and points scored are not easily predicted, which is why they play the games.”
Karen M. Jones