Efficiency in the football-betting market was examined on a month-by-month basis over a 19-year period. Prompted by the mispricing of IPOs in the securities market, we anticipated less-efficient pointspreads in the first month of the National Football League's season (September) than in the three succeeding months. While more wins-to-bets ratios for the 28 NFL teams competing during the 1980-98 seasons were nonrandom in September than in October or November, W/B ratios in December were most conspicuously out-of-line. Possible explanations for a mature market behaving immaturely include an environment in which streaks occur as teams either chase post-season rewards or collapse when no longer contending and the substitution of lesser-known players for injured teammates.
Ladd Kochman and Randy Goodwin. "The Impact of Season Maturity on the Football-Betting Market." New York Economic Review. vol. 31, Fall 2000, p. 27-31
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