Sunday, May 10, 2020

Recommend Counting 5+ run Wins as 3-game sweeps; 2019 data on sweeps when good teams play poor teams

If you play one of the good teams (top 10 records) from 2019 for 20 games against only bad teams (bottom 10 records) the margin of error is huge - the good team would be expected to finish with a record of between 9-11 and 18-2. Factor in that a good team really faces a mix of poor, average and other good teams, and there is more than a one in three chance of poor team finishing ahead of a good team in a 20-game season even though it would be nearly impossible over 162 games.

To cut down on the margin of error we each game as a 3-game series, giving the winning team credit for a 3-game sweep only if they lead by at least 5 runs at the end of the 8th without using their closer, and don't blow it and lose in the 9th. We set this up because it is just as hard to win a 3-games series as to win by 5+ runs (a 14% of each in modern baseball).

For a reality check, we divided the actual 2019 Major League teams into three groups, with the best 10 records categorized as "good" teams,the middle 10 as "average" teams, and the bottom 10 as "poor" teams.

Running the numbers revealed that when a good team played a poor team, they swept the first three games of the series 57 times in 174 series - or 33% of the time. The poor team only swept the good team three times - all in April they the Royals sweeping the Indians and then the Blue Jays sweeping the A's twice. The good teams won 77% of all the series against poor teams - here it is in table form.

1st 3 games of series; top 10 vs bottom 10 teamsTotalPercentage
Good Team Swept 3-game series5733%
Good Team Won 2 of 37744%
Poor Team Won 2 of 33721%
Poor Team Swept Series32%
Total Series in Actual 2019 Season174100%

We originally set up the system of counting 5+ wins in games as 3-game sweeps because it is just about as difficult to do either thing - over time in all series teams win by 5 or more runs 14% of the time and they sweep 3-game series 14% of the time.

We then ran all 627 games between good and poor teams (note this includes 2-game series, and the 4th and 5th games in longer series that were not counted among the 522 games in the 174 series above). While overall teams are just as likely to win a single game by 5+ runs as to sweep a 3-game series (14% of either one), we found good teams were not quite as likely to beat a poor team by 5+ as to sweep them. Here is the breakdown.

All GamesGamesPercentage
Good Team Wins by 5+ Runs15525%
Good Team Wins by 1-4 or extra innings28045%
Bad Team Wins by 1-4 or extra innings14323%
Bad Team Wins by 5+ Runs498%
Total Games in Actual 2019 Season627100%

While the good teams actually swept 19 times as many series as the poor teams (33% to 2%) in 2019, they only won by 5+ runs three times as often (25% to 8%).

We went into this study open-minded on whether we would keep playing the 5+ rule,but based on this study we do recommend it. Here is the impact on your board game league standings based on the 2019 actual results:

  1. Teams will play closer to .500 than the wild variations of a 20-game or so season. In 2019, the good teams would have been credited for about a 62% win record against poor teams instead of the nearly 70% they actually won. This played out when we had the AL a couple of years ago when the Astros, Yankees and Red Sox all finished at 38-22 using our 5+ sweep rule instead of teams turning in ridiculous records as high as 17-3 (an .850 winning percentage).
  2. While it is much easier for a poor team to finish ahead of a good team in a 20-game schedule using the 5+ rule is more realistically difficult for a poor team to beat out a good team in a 20-game schedule that counts as 60+ games because the good team is three times as likely to get the bonus win from the 5+ run rule (25% of the time to only 8% of the time for the poor team).
While having surprise teams pull upsets some of the time is part of the fun of replaying, we do recommend the 5+ run = sweep rule to make the degree of difficulty realistic in your board game. The recommendation we give is to say a team gets credit for a 3 games to 0 sweep if they win the game AND they led by 5 runs or more at the end of the 8th inning without having used their closer.

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