Researchers at the University of Chicago have determined that the impact coaches have on a team's success is significant, and that certain coaches are more effective than others.
"How Much do Coaches Matter?" was presented earlier this month at the MIT Sloan Sports Analytics Conference in Boston. The study, by Christopher Berry and Anthony Fowler of the U. of Chicago's Harris School of Public Policy, acknowledges that coaches often take the credit or the blame for their team's success or lack of it, and are compensated handsomely for bearing that burden. "Although we have anecdotal evidence that coaches matter, the sports analytics literature has generally concluded that they do not," the authors wrote. "We present a new method for estimating coach effects, which we call Randomization Inference for Leader Effects, or RIFLE."
According to research news website Futurity, the researchers first created the approach to estimate the effects of political leaders on various economic and policy outcomes. The method holds promise for additional research to assess the impact of individual coaches, as well as better understand why and how coaches matter. The authors applied RIFLE to MLB, NBA, NHL, NFL, college football and college basketball. "We detect coaching effects in all sports," wrote Berry and Fowler. "Our estimates generally imply that coaches explain about 20-30 percent of the variation in a team’s success."
Some key findings, as reported by Futurity:
- MLB managers affect runs scored, runs allowed, run differential and victories. They have greater impact on runs allowed versus runs scored.
- NFL coaches affect points allowed and the point margin. They significantly affect the number of fumbles and penalties a team commits.
- Coaches matter more in college football than in the pros. They significantly affect points scored, points allowed, point differential and victories.
- Coaches are highly significant in both NBA and Division I college basketball outcomes, influencing points scored, points allowed, point differential and victories.
- NHL coaches matter, although they matter much more for goals allowed than goals scored.
"Coaches are often credited or blamed for their team’s success or failure, and are compensated as if they are among the most important assets a franchise possesses," says Berry, a professor at the Harris School. "We find that coaches do, in fact, matter — and suggestions that coaches are interchangeable, which has been the dominant view in the sports analytics community, are not true. In every sport we studied, we found that coaches impact variables that contribute to a higher winning percentage."
Adds associate professor Fowler, "Although virtually every aspect of player performance has been examined since the recent emergence of sports analytics, we wanted to bring the same level of rigor to coaches as there is for everyone else on the field at a major sporting event."
