A common maxim in baseball is that good pitching always beats good hitting and while this may be true it does create low scoring affairs. But does this maxim hold true on the score board? What is the average number of runs scored in an MLB game? How has this changed over the years?
For those looking for a quick answer: during the 2013 MLB season the average number of runs scored in an average game was 8.33 runs per game. On a per team basis, this equates to 4.17 runs per game. During the 2013 MLB season, a total of 20,255 runs were scored over 2,431 games.
But how has that changed over the seasons? Here is a chart that plots out the average number of runs scored per game over the last 24 seasons:
As you can see, there has been two defined periods - one of growth between 1992 and 2000 where runs per game rose from 8.23 runs per game to a peak of 10.28; and a period of decline between 2001 and 2013 where runs per game declined to 8.33 runs per game in 2013.
This begs the question of what is behind these changes in runs scored in the MLB. Two big reasons for it are changes in strikeout rates and home runs.
Rise of the Strikeout and Fall of the Home Run
Pitchers are getting a lot better at striking out batters as illustrated by the chart below:
Since 2005, the total number of strikouts thrown during the season has rose every single year from 30,644 in 1995 to a new high in 2013 of 36,710, which means fewer players are reaching the bases.
In contrast to the growth of the strikeout, is the decline of the home run as illustrated by the chart below:
As you can see from the above, home runs peaked in 2000 where there was a total of 5,693 home runs but since then there has been a continued decline of dingers, which are now hovering around the 4,600 level (4,661 home runs in 2013). You can read more about the reasons for the decline in home runs.
Year-by-Year Look At Runs Per Game
Overall, runs continue to be on the decline but there is likely a bottom to be found in the near future. That is unless pitchers continue on their insane strikeout pace.