When the 2021 regular season concluded, there was the following exchange in the “Hey Bill” section of the Bill James Online baseball community, with Bill’s response starting at “Answered”:
Hey Bill!
Is it possible to calculate an expected number of 1-run games for a team in a season? The reason I ask is that the Mets played in 66 1-run games this year, 40.7% of their games. That seems like a whopping big number . . . but is it?
Thanks
Kevin
Asked by: kgh
Answered: 10/4/2021
It's a very large number, but I wouldn't know how to calculate an expected number. I don't even know what the variables would be. I suppose one-run games are slightly more common among teams which are near .500, and obviously they would be significantly more common in a low-run environment than in a high-run environment.
I built a dataset to answer those questions and a few more that popped up along the way.
Let’s start with the easiest one:
The 2021 Mets played 66 one-run games or 40.7% of their games. Is that a whopping big number?
Yes, that is a big number, but not “whopping” big.
The Mets did play 66 one-run games, with 13 of those in extra-innings and 53 in “regulation”. They played 18 total extra-inning games. This gave them a total of 71 games that were decided by one run or in extra-innings. Several teams listed below played more one-run games than the Mets did in 2021.
Baseline
The historic average of all games that are one-run or go into extra-innings is 32.05% or 52 per 162-game season.
Dataset
I took the game logs for every team/season from 1900 to 2020 and put them in run differential categories. I called extra-inning games category 0. Double-digit run differentials went into category 10. The remaining games were all put in the slots corresponding to the run differentials. For this study, we’re only concerned with the games in slots 0 and 1. What I didn’t do is categorize the extra-inning games in a slot corresponding to the final outcome. In this case, we’re trying to project the number of one-run games, so I thought it would be more instructive to look at game states at the “end of regulation”. Once a game goes to extra-innings, especially with the zombie runners introduced in 2020, it might end up with a differential of more than 1 run. It seems to me the conditions for producing an extra-inning game are the same as for one-run games.
What is the record for most one-run games?
The 1971 Astros and the 1993 Royals both played 58 one-run games (not including extra-inning games). That is also the record for percentage of one-run games.
1. Astros 1971, 35.8% (58 games, 25-33 record) 1. Royals 1993, 35.8% (58 G, 30-28) 3. Reds 1946, 35.7% (55 G, 22-33) 4. Dodgers 1968, 35.2% (57 G, 27-30) 4. Phillies 1968, 35.2% (57 G, 31-26) 4. Pirates 1918, 35.2% (44 G, 21-23)
Which teams won the most one-run games?
1. White Sox 1972, 35-13, .729 WPct 2. Reds 1940, 34-11, .756 (won World Series) 3. Cleveland 1917, 33-17, .660 3. Yankees 1968, 33-22, .600 5. Amazing Mets 1969, 32-17, .653 (won World Series) 5. Astros 1979, 32-24, .571
The year of the pitcher, 1968, is well-represented here and elsewhere in this study, showing the strong influence of a low run environment on tight games.
Which teams lost the most one-run games?
1. Yankees 1966, 13-35, .271 WPct 2. Giants 1946, 20-34, .370 3. Reds 1907, 10-33, .233 3. Reds 1946, 22-33, .400 3. Astros 1971, 25-33, .431
What is the record for extra-inning games played?
These are all extra-inning games, whatever the run differential ends up being.
1. Red Sox 1943, 19.1% (29 games, 15-14 record) 2. Browns 1943, 18.4% (28 G, 10-18) 3. White Sox 1922, 18.2% (28 G, 16-12) 3. Tigers 1957, 18.2% (28 G, 13-15) 5. Cleveland 1943, 17.7% (27 G, 13-14)
Which teams won the most extra-inning games?
1. Cleveland 1949, 18-1, .947 WPct 1. Pirates 1959, 18-1, .947 1. Expos 1988, 18-7, .720 4. Braves 1999, 17-5, .773 (World Series runner-up) 4. Diamondbacks 2013, 17-8, .680
You probably recognize the ’59 Pirates. Roy Face set the pitcher’s winning percentage record for the Pirates that season, going 18-1. The team only went 60-75 in games that ended in 9 or fewer innings. You might expect regression the following season; but, of course, the Pirates were 1960’s world champs and they won more than 70% of their extra-inning games, going 12-5.
Which teams lost the most extra-inning games?
1. Browns 1943, 10-18, .357 WPct 2. Phillies 1924, 7-17, .292 2. Pirates 1984, 9-17, .346 2. Reds 1942, 9-17, .346 2. Dodgers 1967, 10-17, .370
What is the record for most combined one-run and extra-inning games played?
1. White Sox 1968, 47.5% (77 games, 33-44) 2. Reds 1946, 47.5% (73 G, 30-43) 3. Astros 1971, 46.9% (76 G, 33-43) 4. Reds 1916, 46.4% (71 G, 29-42) 5. Marlins 2014, 45.1% (73 G, 38-35)
Which teams won the most combined one-run and extra-inning games?
1. Orioles 1970, 45-19, .703 WPct (won World Series) 2. Yankees 1943, 44-23, .657 (won World Series) 3. Reds 1940, 42-19, .689 (won World Series) 3. Mets 1969, 42-23, .646 (won World Series) 3. Orioles 1974, 42-23, .646 (</theme>) 3. Giants 1978, 42-29, .592
Which teams lost the most combined one-run and extra-inning games?
1. White Sox 1968, 33-44, .429 WPct 2. Astros 1975, 16-43, .271 2. Reds 1946, 30-43, .411 2. Astros 1971, 33-43, .434 5. Pirates 1986, 19-42, .311
In Part 2, we’ll dive into this question: Is it possible to calculate an expected number of 1-run games for a team in a season?
Thanks for reading!