Having the Best Playoff Win Percentage, and STILL Losing the World Series? That's Baseball!

I thought this picture was adorable! They're rocks! Playing baseball!

​Every Friday, the political and sports analytics website FiveThirtyEight offers up problems related to the things we hold dear around here, math, logic and probability, in their popular Riddler column. When we get the chance, we enjoy checking out these puzzlers, and the solutions that oftentimes are the exact opposite of what you initially think!

This week, the Riddler offered up a problem relating to the MLB postseason and winning percentages, so we know we had to take a crack at it.

“The Major League Baseball playoffs are about to begin. Based on the current playoff format, what is the best possible winning percentage a team can have in the playoffs without winning the World Series? And what is the worst possible winning percentage a team can have in the playoffs and still win the World Series?

Extra credit: How close to these extremes has any actual team come?”
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The MLB postseason consists of 4 rounds, with the first round being an optional single game play-in round that only four teams compete in, the Wild Card. The next round, the Divisional Series, consists of a best-of five games. The Championship Series and the World Series both consist of a set of best-of seven games. ​

(Source: MLB.com)

We know that winning percentage is calculated by dividing the number of games won by the number of games played. Therefore, winning the most games in the fewest number of games possible will yield the highest winning percentage. Conversely, winning the fewest games in the most number of games possible will result in the lowest winning percentage.

The minimum number of games played by a team through the World Series is 11. This is determined by a team not playing in the optional wild card, and then sweeping the divisional, championship, and World Series. 3 + 4 + 4 = 11. Likewise, the maximum number of games played is 20, playing the wild card, and then taking every round to their maximum length. 1 + 5 + 7 + 7 = 20. These two numbers are constants, and are necessary for both parts of this puzzle.

Let’s tackle the first part of the question first. "What is the best possible winning percentage a team can have in the playoffs without winning the World Series?"

For a team that made the World Series but did not win, the minimum number of games won is 7. This is calculated by not playing the wild card, winning the divisional and championship series, and then being swept in the World Series. 0 + 3 + 4 + 0 = 7. The most number of games won is 11. This arises from a team winning the wild card, winning the division and championships series, and then taking the World Series to 7 games, before losing. 1 + 3 + 4 + 3 = 11.

By using a nested for loop, we can quickly generate every possible winning percentage for a team that makes, but does not win the World Series. The only complications here was making sure that we played at least 4 more games than we won, since we lost the World Series, and ensuring that we have played (and won) the wild card to play the maximum amount of 20 games.

The best postseason winning percentage without winning the World Series is winning 11 games while playing 15 games for a winning percentage of 0.733.

Quick side note, you can run any of these Python snippets using your browser through emulators such as this one.

The 15 games stem from playing, and sweeping, the wild card, divisional, and championship series, and then taking the World Series to 7 games before eventually losing. 1 + 3 + 4 + 7 = 15. By the definition of winning percentage, this answer makes sense. The most number of games a team can win and still lose the World Series is 11, while the minimum number of games to do so in is 15, by the scenario described above.

On to Part 2!

"What is the worst possible winning percentage a team can have in the playoffs and still win the World Series?"

For a team that made the World Series and won, the minimum number of games won in the entire postseason is 11. This is calculated by not playing the wild card, winning the divisional and championship series, and then winning the World Series. 0 + 3 + 4 + 4 = 11. The most number of games won is 12. This arises from a team winning the wild card, winning the division and championships series, and then winning the World Series. 1 + 3 + 4 + 4 = 12.

By using another nested for loop, we can quickly generate every possible winning percentage for a team that makes and wins the World Series. The only complications here was making sure that we played at least as many as games as we won, and ensuring that we have played (and won) the wild card to play the maximum amount of 20 games.

The worst winning percentage and still winning the World Series is winning 11 games while playing 19 games for a winning percentage of 0.579.

This result may not be as intuitive as the first part. The scenario of playing 19 games results from not playing the wild card, and then taking each of the divisional, championship, and World Series rounds to their maximum lengths.

By definition, the worst winning percentage arises from winning the fewest possible games in the most number of games possible to play. If we played the wild card, won the World Series, and maxed out every series, we would have a winning percentage of 12/20 = 0.6. This is actually higher than not playing the wild card and maxing out every other series, 11/19 = 0.579.

So how close to these extremes has any actual team come since the inception of the wild card era in 2012? We went to Baseball-Reference to find out.

Here are the postseason winning percentages for every team that lost the World Series since 2012:

As you can see, the 2014 Kansas City Royals actually had the highest possible winning percentage for a World Series loser! The 2014 World Series was a strange one, featuring not one, but two wild card teams, one of which was the Royals. In addition to winning the wild card game, the Royals also swept the divisional round against the Angels, and then swept the Orioles in the championship round, before losing to the Giants in the World Series in 7 games. The Royals’ mark of 0.733 is also the highest postseason winning percentage of any World Series participant since 2012, including winners.

The team that came the closest to winning the World Series with the lowest possible playoff winning percentage was last year’s champion, the 2017 Houston Astros. While they avoided the wild card game, and took both the championship and World Series rounds to the maximum of 7 games, the Astros beat the Red Sox in four games in the divisional round, one game short of the maximum of five. Perhaps this will be the year…

Do you think we’ll ever see another World Series of two wild card teams? Should the MLB playoff structure be changed? If so, how in your opinion? What about no divisions and a new playoff format where 30 teams are split between AL and NL, with six teams in each league making the postseason?

As always, our code and data can be found on GitHub. If you follow the Riddler as well, or if you have any thoughts or opinions, we would love to hear them in the comments or on Twitter! The correct answers will be posted to the Riddler column next week, hopefully we are correct!

The SaberSmart Team

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