Why Sportsbooks Almost Never Predict MLB Winners Correctly
When baseball season starts, the earliest bets that come in are futures bets, which are wagers on the World Series winners. Usually, the odds on long-shots are as high as they’re going to be. Futures odds in the low to mid-thousands tend to decrease from the preseason through the World Series. However, futures odds at the beginning of the season are a bad guide to who will win the World Series. In fact, one of the best ways to guess who will win the World Series is to bet against the most favored teams.
And we have the data to prove it.
History Doesn’t Lie
There’s a great site that archives sports betting odds from previous years. Their data set on MLB futures odds go all the way back to 1985. So, we can see how well sportsbooks guessed the World Series winners from 1985 to 2020.
They don’t do great. Out of 35 years, here’s how many teams were in different groups of odds:
The first lesson you should take away from this table is that most World Series winners have long odds during the preseason. About a third of the winners are in the +400 to +900 range at the start. But almost half of all World Series winners have odds between +900 and +4900. Sportsbooks and sports journalists do not predict World Series winners well.
Only five teams had odds lower than +400 during the preseason – and two of them were the Yankees during their late-‘90s hot streak. Excluding those two, that’s as many calls as championship teams with odds above +4900. Winners can come from anywhere, but they usually come from teams that no one’s expecting during the preseason.
So what gives?
||World Series Winners In Odds Range
|+100 to +400
|+400 to +900
|+900 to +1900
|+1900 to +4900
||Less than 2%
Life’s Hard and Unpredictable
There are so many things that go into a great team. Every team member has to not only pull their weight but also excel. The coaching staff has to combine intense conditioning with sound tactics. And of course, they have to do that better than the rest of the teams. There are so many moving parts from each team member’s personal life to the team dynamics throughout its performance that season. There are so many unknowns that the last season’s play data quickly becomes outdated.
That’s the other underrated flaw in using preseason odds to predict World Series winners. Because they draw from the previous season to predict who will win next, naturally, the most recent winners tend to be favored.
However, that data quickly becomes useless. Players are traded. Coaches leave, retire, and get fired. The talent pool is constantly churning, making accurate season predictions next to impossible.
Why Sportsbook Odds Shouldn’t Be Used For Accurate Predictions
It’s not the sportsbooks’ fault that futures odds don’t predict the future. That’s only part of their job. Sportsbooks are also responding to the hype from fans. We’ve written before about how Trump voters skewed odds on sportsbooks overseas. Even though the polls turned against him, sportsbooks overseas still showed Trump as the favorite. Trump bettors put so much money on him that sportsbooks overseas had to offer great odds on Biden to balance their liabilities out. The sportsbook odds lagged behind the polls.
Sportsbook odds offer a snapshot of what oddsmakers think will happen. But it quickly becomes morphed by bettor behavior. It’s as much a snapshot of what bettors think as what sportsbooks think.
Finding the Blind Spot in MLB Predictions
When you’re looking for teams to bet on to win the World Series, don’t throw your money away on the favorites. Remember, the winning team may undergo major changes before the season starts up again. Other teams will likely improve from the season before, too. No team wants two terrible seasons in a row – good owners will make sure of it. Betting on change is more reliable than betting on things to stay the same.
However, that still leaves you with many teams to choose from. Thirty teams leave plenty of room to narrow guesses down and still choose poorly. However, bettors should take heart that preseason odds can be such poor predictors for the World Series winner. Unlikely winners give bettors the chance to win big.
However, that won’t be true every year, either. We could have another late-‘90s dynasty that dampens the odds on the winner. (Unlikely, but it would be exciting.) But bettors can spend their time focusing on long shots when they’re looking at futures. The safe options just don’t cut it.