Baseball has been declining in popularity (at least as measured by game attendance figures) and one possible reason for this decline is the increasing length of games. Below I have graphed the mean length of a 9-inning game for the past 20 seasons. Interestingly, the mean length of a baseball game dropped from 2000 to 2005, but it has shown a steady increase from 2005 to the recent 2019 season. The mean length of a 9-inning game in 2005 was 166 minutes (about 2 3/4 hours) and the mean length in 2019 has risen to 185 minutes (over 3 hours). Games in the post season seem to be especially long and the patient baseball fan sometimes has to wait after midnight to watch the final pitch and see the outcome of a playoff game.
Although it is obvious that baseball games are getting longer, the reasons for the increase in game length are not as clear. In this blog we’ll propose several explanations for the increasing game length and use several graphs to provide some insight into these possible explanations. From this exploration, we’ll see that there is one issue that may be the main contributor to this problem and we’ll discuss what steps Major League Baseball can take to address this issue.
Three Possible Explanations
- Possible Explanation 1. Although a baseball game is divided into innings, a game essentially is a sequence of plate appearances. When there are many runs scored in a game, there will tend to be more runners, more hits, and more non-out plate appearances and longer games. That motivates the first possible explanation. Perhaps the increase in baseball length over seasons is due to an increasing amount of hits, scoring and plate appearances in recent seasons.
- Possible Explanation 2. Each plate appearance is a sequence of pitches which ends with a strikeout, a walk, or a ball put into play. (I’m ignoring some other outcomes which happen rarely.) It takes time to throw each pitch. So perhaps batters are having longer plate appearances, that is seeing more pitches, and that is the reason for the longer games.
- Possible Explanation 3. Maybe batters aren’t facing more pitches in a plate appearances from season to season, but the pitchers are taking longer to throw these pitches. Although MLB has talked about creating a 20-second rule, pitchers currently are not forced to pitch within a particular time frame. Maybe slower pitching is the cause of the increasing game lengths?
Let’s look at each of the possible explanations for the increasing game lengths in the past 20 seasons.
More Plate Appearances?
Let’s first look at the number of PAs (plate appearances) in a game. I’ve graphed the mean number of PAs in a game against season. Actually the average number of PAs has dropped from 2000 to 2015 and is showing a slight increase in recent seasons. No, there aren’t (on average) more PAs in a game. The change in PAs does not appear to be causing the increase in game length.
Longer Plate Appearances?
Next let’s look at the length of a PA and see how it has changed over seasons. Graphing the mean number of pitches per PA, we see a steady increase in the last 20 seasons — batters were taking 3.7 pitches per PA in 2000 and now they are taking 3.9 pitches per PA. Generally it seems that batters are becoming more patient and taking more pitches. (The free swinger is becoming rare.)
Since we’ve shown that the number of PAs has shown some decrease, one might wonder how the number of pitches per game has changed. So I have graphed the average number of pitches in a nine-inning game below. Although this mean number of pitches was pretty level between the 2000 and 2015 seasons, it has grown steadily in the last four seasons.
Longer Time to Pitch?
Not only are we seeing more pitches per game, the time to throw these pitches is changing. Here’s how I measured the time to pitch. For a particular season, I fit a simple linear regression to the (Number of Pitches, Duration) data and the slope of this line is the estimate of the time to take an additional pitch. I plot these season regression slopes in the plot below. We see a increasing trend of this “mean time per pitch”, although this time measurement has appeared to stabilize in recent seasons.
What Have We Learned?
- We suggested three reasons for the increasing game lengths — more plate appearances, longer plate appearances, and longer times to pitch. Our analysis is somewhat superficial since we are focusing only on changes in the mean values over seasons, but we can draw some conclusions. We don’t see an increase in the mean number of PAs. But plate appearances are clearly getting longer (more pitches per PA) and I wouldn’t be surprised if PAs continued to lengthen. Also, pitchers are taking longer, on average, to pitch, although the mean time to pitch appears to have stabilized in recent seasons.
- Time to pitch actually is more complicated than my analysis suggests. When one dissects the time of a baseball game, we collect the time between pitches to the same batter, the time between pitches to successive batters, the time between innings, the time to make a pitching change, the time for a conference on the mound, the time for a challenge, etc. David Smith did an extensive analysis of the time between pitches for the 2018 season in the recent Baseball Research Journal. For example, he finds that the mean time to pitch is 23.8 seconds for pitches to the same batter and the average time for the 7th inning stretch was 3 minutes and six seconds. (Breaking this down further, 7th inning stretches with “Take Me Out to the Ballgame’ and “God Bless America” take, on average, 2:53 and 4:04.)
- What can Major League Baseball do about this? Well, some factors such as the number of pitches per PA are outside of MLB’s control — the number of pitches relates to the batter’s plate discipline. MLB can regulate the time between pitches, but I don’t know if, say a 20-second rule, will impact the total length of the game very much. Baseball has made some recent changes such as the the intentional walk rule and the “must pitch to three batters” rule, but I am guessing that these particular rules will have minimal impact on the game length.
I’ve explored this length of game topic in some previous posts:
- This “Length of baseball games” post demonstrates how the length of a game is strongly related to the number of pitches.
- This “Dissection of the time of a baseball game” post explores all of the times between pitches for all games played on a particular day.
- This “Pace stats in baseball and tennis” post explores the time between pitches for eight pitchers in the 2015 season.
- Data. All of this work was done using Retrosheet data. The Retrosheet game logs datasets were used to extract the time of game variable for all games in these 20 seasons. This information was merged with the number of pitches and number of plate appearances variables from the Retrosheet play-by-play datasets. You can use Statcast data if you are interested in exploring the times between pitches for individual games.
- Code. My Github gist site provides all of the R code for this particular analysis.