Know Your Probabilities Better Than The Bookies

In his article for The Economist, David Sumpter, a professor of applied mathematics at the University of Uppsala, Sweden, and the Author of the book “Soccermatics: Mathematical Adventures in the Beautiful Game” drops a few interesting thoughts:

1) “Gambling is not about picking winners. The trick is to know your probabilities better than the bookies.”. Know Your Probabilities Better Than The Bookies!

2) Each league / championship is different in its own way, you need to study them one by one, and build prediction models for each one, individually. For instance, a model that works for predicting the English Premier League, isn’t directly transferable to another championship. Prof. Sumpter says that “for the English Premier League, the bias against draws between well-matched teams might be explained by the media hype building up to these games. The newspapers carry stories strongly contrasting the two teams, and punters are tempted to opt for one side or the other, neglecting the correct probability of a draw. The same isn’t true for other leagues. When I tested my model on the Championship and lower leagues, without placing bets, I found that draws between well-matched teams were not undervalued on betting sites.”

3) Among all models the Author tried, the “odds bias model” turned out to be the most reliable. “Many betting markets exhibit a phenomenon known as “long-shot bias”, where the odds are better for favourites than for “long shots”. The bias can be explained by punters being attracted by the potential of big profits offered by large odds, and undervaluing the smaller gains to be had by betting on the favourite (and bookmakers adjusting their odds accordingly).”
Prof. Sumpter found “a long-shot bias in earlier Premier League seasons. For example, in 2014-15, putting money on Chelsea, Arsenal and Manchester City against teams lower in the table would have given a small but reliable week-on-week pay-off. Big teams win slightly more often than predicted by the bookmakers’ odds. This bias disappeared during the 2015-16 season, with big teams performing worse than expected, and with “long shots” Leicester City defying the odds. Not only did some bookmakers initially offer Leicester at 5,000 to 1 to win the league, but they were also undervalued in almost every match they played.”

Read the full article here: https://www.1843magazine.com/features/the-daily/how-i-used-maths-to-beat-the-bookies