There are always x-factors that hamper predicting sports. It could be something crazy, like the finish to the Dolphins vs Patriots game at the weekend. Perhaps it could be something you just can’t legislate for, such as players getting injured at crucial moments in the season. Indeed, sometimes a team itself is just not as good as we think them to be.
Very often, of course, bookmakers get it wrong. But it should be noted that statisticians get it wrong too. If either didn’t, Hillary Clinton would be President of the United States and Tom Brady would have about nine Super Bowl Rings. Here’s a question though: how do the statisticians and bookmakers match up when it comes to comparing odds and implied probability? Do they always agree? Would you expect sportsbooks to be less generous, given that they may take a theoretical cut as a house-edge of sorts?
Well, let’s compare some bookmakers odds for Super Bowl LIII and compare them against the statisticians’ take on this event at FiveThirtyEight, the polling data and prediction website headed by Nate Silver. Just a note that these are being compared before the Week 15 round of games, and the odds and probabilities are thus subject to change.
Saints betting favorite and statistical favorite
Starting with the favorite for the Super Bowl – New Orleans Saints. FiveThirtyEight gives the Saints a probability of 27% of winning the Super Bowl. However, checking the latest NFL betting from Canadian betting sites shows you can find the Saints at 7/2 (+350). That has an implied probability of about 22%. The further we are from that 27%, the more seemingly generous the odds are, so that’s a pretty good price for the Saints if you believe in FiveThirtyEight’s predictions. In fact, to match the probability from FiveThirtyEight, you would expect odds of around 19/7 (+270).
What about the second-favorite, fellow NFC team Los Angeles Rams? Well, FiveThirtyEight has given them a 14% chance of winning it all in Atlanta in February. Bookmakers seem to have settled on their chances too, with several outlets going for 4/1 (+400). As you might expect, that gives them an implied probability of 20%. This is greater than the probability from statisticians, so it suggests bookmakers think more of the Rams that the numbers people do.
Bears have surprised many
However, that’s the two favourites, so why not take a look then at an outside favorite for the Super Bowl? Someone with an almost guaranteed chance to win their division and make the Playoffs – the Chicago Bears. FiveThirtyEight rate the chances of the Bears at just 4% and that suggests the odds should be about 24/1 (+2400). But you cannot find odds like that for the Bears at this stage of the season, with the best odds looking about 12/1 from William Hill. That’s almost half of what they should be if they were following the statistics.
What do we learn from this? Not much, as it’s hard to argue with what is the purest method. For example, bookmakers will react to money placed on particular teams, so that can sometimes slightly skew odds in favor of popular franchise. It is, however, interesting to consider that your bet on the Saints might be slightly more value for money than your punt on the Rams – according to the numbers gurus, anyway.