The Reverse Favorite—Longshot Bias in the National Hockey League: Do Bettors Still Score on Longshots?

The favorite—longshot bias, the tendency of bettors to underbet favorites and overbet longshots (underdogs), has received considerable attention in the economics and finance literature. Although the bias is prevalent in racetrack betting, with pari-mutuel odds, researchers have detected a reverse bias in two fixed-odds betting markets in the United States. A weak bias was documented for Major League Baseball for 22 seasons. It was also found to be present in the National Hockey League betting market and was of sufficient strength to allow for profitable wagering opportunities. This article analyzes 10 additional seasons of hockey wagering. The bias is sustained for the first three seasons but disappears in the last seven seasons as the market converges to efficiency. This contrasts with the baseball betting market, where the bias persists.