Historical Baseball Game Length: How Long are Baseball Games?
As the 2023 baseball season is getting underway, one of the most talked about topics is the average length of a baseball game. Just exactly how long are baseball games? From the 2019 season up through the 2022 season, the average game length came in at just over three hours.
It isn’t a secret that games have gotten longer and the slowing of the action has probably had an impact on baseball’s popularity. New rules this year are supposed to be shortening the games in a bid to win back fandom and viewership. The new rules seem to be working.
Through the first week of the 2023 season, the average game length is down to two hours and forty minutes. Whether or not the shorter games have the intended effect on popularity is yet to be seen. Still, fans are getting out the door 20 minutes earlier than they were in recent years.
Because the question of the average length of baseball games is fresh in everyone’s mind, we wanted to look at historical trends around the topic. We’re going to look at statistics surrounding the length of baseball games through the history of the league to provide color and context to the discussion.
All the code used in the analysis in this article is the “How Long are Baseball Games” repo on The Data Jocks Github. The data is sourced from this website.
The Rule Changes Before the 2023 Season
There were many rule changes prior to the 2023 MLB season but two of these were designed to address the average length of baseball games. These are:
- The pitch clock
- New pickoff rules
The first one is the big one. This year, a pitch clock has been introduced to limit how long a pitcher has to make his delivery. Pitchers now have 20 seconds to pitch with a runner on and only 15 with the bases empty. This ESPN article indicates that more than 100 pitchers last year took longer than this to pitch on average. Certainly this rule change will help speed the game.
A second rule limits what a pitcher is allowed to do when trying to pickoff a runner on base. While this rule is primarily designed to encourage stolen base attempts, it will also indirectly decrease how long a baseball game is. To read more about pickoffs, check out our previous article looking at the definition of balks in baseball.
Both these rules were tried in the minors before being brought up this year and resulted in quicker, more exciting games. Let’s now turn to look at the core of the problem: the average length of baseball games.
The Average Length of Baseball Games Through History
It is no secret that the average length of baseball games has been increasing for a long time. Before showing the data graphically over the years, here is how long a baseball game is by decade. We have data about baseball game length back to the 1920s:
Decade | Avg Length |
|---|---|
1920s | 1:55 |
1930s | 1:58 |
1940s | 2:07 |
1950s | 2:14 |
1960s | 2:34 |
1970s | 2:33 |
1980s | 2:33 |
1990s | 2:49 |
2000s | 2:56 |
2010s | 2:54 |
2020s | 3:04 |
The data so far this year suggests that the game length might have dropped back down into the low 2:40 range. Games haven’t been that short since the 1980s. This is a fairly dramatic rolling back of the clock.
While the by-decade data is useful, it can be even more compelling to look at the trend over time. The plot below shows how the length of a baseball game has trended since the early 20th century.
This plot shows a nearly constant increase in the length of games from the 1920 until now. Left unchecked, this slowing of the game would continue to deter fans from tuning in regularly.
Baseball Game Length Percentiles
A different way to look at “how long is a baseball game” is through percentiles/quantiles. While the average tells us the night-in, night-out expected watch time, sometimes games go much longer or much shorter. The table below contains selected percentiles for baseball game length in 1920, 1970, and 2014 (the longest year we have in our database).
1920 | 1970 | 2014 | |
|---|---|---|---|
5th Percentile | 1:25 | 2:01 | 2:30 |
25th Percentile | 1:40 | 2:18 | 2:49 |
Median | 1:50 | 2:31 | 3:04 |
75th Percentile | 2:02 | 2:47 | 3:21 |
95th Percentile | 2:32 | 3:20 | 4:00 |
This data says that the SHORTEST modern day games are about the same length as the LONGEST games from early in baseball history. Even crazier is that 1 in 20 games last year, maybe one every other day or so, went for more than 4 hours. Nearly every other day in modern baseball there is a game that lasts twice as long as an average 1920s game.
The graph below shows the 5th, 25th, 50th, 75th, and 95th percentiles for baseball game length over the data set we have.
Correlation of Game Length With Runs Scored
The argument many fans present is that, because the games have gotten longer and more drawn out, the games have gotten less interesting. This would only be true if there is less happening per minute of game time. To say that another way, if the games are longer because there is more scoring, then the added game length probably isn’t turning fans away.
Let’s look to see if scoring increases have caused the lengthening of the game. Take a look first at the plot below which shows how scoring has evolved over time.
This plot shows that scoring was at its highest in the 1930s and in the late 90s/early 200s. In the last 15 years, though, pitchers have begun to dominate again. The same is true in the mid 20th century especially in the 1970s.
The more interesting chart is to plot runs scored per hour of game time. The plot below shows runs scored per hour over all seasons back to 1915.
This plot confirms what we’ve expected to be true. From its peak in the early-mid 20th century to now, the amount of runs per hour has been nearly cut in half. More importantly, the runs per hour has been dramatically dropping since the early 2000s. You can see this by noticing the line on the very right hand side of the above plot dropping like a rock since that time.
Less action per minute and longer required attendance leads to an overall worse product,
Do Certain Teams have Longer Baseball Games?
While we’re talking about the length of a baseball game, we also want to see if certain teams have historically played faster or slower than others. We looked back at all the games each team has played since the 2000 season. For each team, we computed the average length of their games.
Then, we computed the average length of all games for all teams since 2000. By subtracting off the league average, we can figure out which teams had the longest and shortest games relative to the rest of the league.
The plot below shows the 6 teams with the longest games since the 2000 season.
Similarly, the teams below have had the shortest games since the 2000 season.
What really stands out to me is that both Boston and the Yankee’s games are much longer than everyone else’s. On the second plot, these numbers don’t strike me as odd – somebody has to have the shortest games just by pure random chance and these numbers feel plausibly within random variation. The Yankees and Red Sox games have been a full 10 minutes longer than the rest of the league. This feels quite significant.
Math isn’t about feeling though. We can actually look mathematically if these feelings are correct. The remainder of this section is simply a fun mathematical exercise.
Is this outside the realm of normal variation? I am not aware of any t-tests to see if the maximum value of a sample is larger than it should be. There probably exists a Kolmogorov-Smirnov statistic that would help. However, we can make an attempt using the central limit theorem.
Let’s assume the set of team game lengths relative to league average is normally distributed. The mean will be 0 by definition and we computed the standard deviation to be 3.2 minutes. This would mean that 68% of the teams in the league should have had an average game length within 3.2 minutes of average.
Now, remember that the percentiles of a random sample are approximately uniformly distributed so that we expect the maximum value in a sample of length 32 to be at roughly 97th percentile. This is a z-score of about 1.88.
This means that we would expect the team with the longest games to have games roughly 1.88\cdot 3.2=6 minutes longer than average. To have both Boston and the Yankees significantly larger than this means that there is likely something that causes the Red Sox and Yankees to consistently have longer games. That is, it probably isn’t just due to random chance.
The Length of Baseball Games Going Forward
At the beginning of the 2023 season, it seems like the measures the league has taken to counteract the length of baseball games is working. Games have decreased in length by twenty minutes so far. Whether or not this has an effect on viewership and popularity, though, is yet to be seen.
So, while we started by asking “how long is a baseball game?” maybe a better question is “how long should a baseball game be?”.
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