It used to be that when August ended, Major League Baseball fans had a pretty good idea of which teams were going to contend for the world championship. Those were the days before the number of divisions in each league increased from two to three and MLB also introduced the wild card, which gave a chance to the best teams in baseball that didn't win their division.

Is that still true? And if it is, with sports betting having become so popular, is it worth wagering on the teams with the best odds of winning the World Series at the end of August?

As we write this, we have reached that point in the 2023 season, making these timely questions. Better still, we had no idea what the answer to the questions might be before we took on the challenge of answering them as they had been posed to us.

Here's how we went about answering them. We tracked down the historic odds Las Vegas bookmakers had given each major league baseball team in each season from 2012 through 2022, omitting the coronavirus pandemic-impacted 2020 season that is too different from a regular season to be used for comparison. These years represent what we'll call the modern era for major league baseball's postseason competition.

From 2012 through 2021, that format awarded ten teams in both the American and National Leagues with the opportunity to compete to win the World Series in postseason play, which expanded to twelve teams in 2022. In this format, the three teams from each league that win their divisions get an automatic invitation to post-season play. Then the leagues award several wild card slots to additional teams in each league with the highest regular season winning percentages that didn't win a division title. From 2012 through 2021, that was two extra teams in each league, which expanded to three extra teams in each league starting in 2022.

For our analysis, we only care about the teams Las Vegas bookmakers thought had the best odds of going on to win the World Series as of 1 September during these seasons. In the following table, we've presented the lines for the top three ranked teams in each full season from 2012 through the 2023 season-to-date, only omitting 2020's pandemic-lockdown shortened season that isn't really comparable with the others. We've then indicated which team actually won the World Series and how much money a bettor would have if they wagered $100 on each of the top three teams, who then may or may not have gone on to win the World Series. Here's the table:

The odds in the table represent how much a bettor would win if they placed a simple $100 money line bet on 1 September for the indicated team going on to later win the season's World Series title. If one of these teams win, they would get the $100 they bet on it back plus the payout indicated by the odds. For example, a winning $100 bet on team with a payout line of (+450) would mean our gambler would have $550 (getting their $100 back plus $450 for winning) after the World Series. But since our hypothetical gambler can't predict the future, we've assumed they bet $100 on each of these three teams in each season, so even if one of these teams wins, they would lose the other $200 they bet on the other two teams.

How did our gambler do? First, we found that each of these teams reached the postseason in each full season from 2012 through 2022, so that already gave them a leg up over other teams. But making it into the postseason is only the first hurdle of the challenge. Of these teams, only 4 of Las Vegas' top-ranked teams qualified as wild card contenders, the other 26 were division winners.

Did any of Las Vegas' top-ranked teams go on to win the World Series? Over these 10 full seasons, we find 5 teams managed to hang on and win enough games to claim baseball's world championship. That happened in 2015, 2016, 2017, 2018, and 2022. The winning teams in these years were either ranked first or second by Las Vegas' bookmakers. In only one of these seasons, 2017, did any of the top ranked teams by Las Vegas' odds play each other for baseball's crown.

How did betting on Las Vegas' Top 3 ranked teams work out? In the five seasons where one of Las Vegas' Top 3 teams won the World Series, our gambler would have placed bets totaling $1,500, but would recover $500 and gain $1,965, leaving them with $2,465 in their pocket. That gain seems like it would be a good payout, but that requires ignoring the five other seasons where all of their bets were losing ones. Overall, of the $3,000 they wagered in total, they would have $2,465 left after accounting for all their winnings and losses. That's a net loss of $535 over these ten seasons.

Looking at World Series winners, we find 8 of the 10 teams won their respective divisions, even if the odds of their winning the World Series at the end of August put them outside the Top 3. Only two wild card teams, 2014's San Francisco Giants and 2019's Washington Nationals have won a world championship.

Of the ten World Series that took place over this period, only 2014's fall classic featured two teams that won wild card slots for the postseason. Two additional seasons, 2019 and 2022, featured a regular season division winner against a wild card team. The remaining seven other World Series were strictly between teams that won their divisions during the regular season.

Overall, the expansion of baseball's wild card playoffs have made the outcome of baseball championship race much less wild than we might have guessed. But if you think about it, the bookmakers are the only consistent winners when it comes to gambling on who will win the World Series.

Notes

* Lines from BetMGM on 26 August 2023. We assume these will be reasonably close to the odds that will be recorded for 1 September 2023.

Image credit: Photo by Joshua Peacock on Unsplash.