Tuesday, October 15, 2013

Runs Per Game

I'm in the process of writing a series of posts centered around the Hall of Fame vote that will be announced in December and am collecting some related stats to give context to the numbers I'll use to support my arguments. As is my habit, I tweet some of these numbers out from time to time to see if they resonate with people, and I did that last night and was stunned by the response. It delayed me watching "The Walking Dead" by a full hour (VERY good episode, by the way).

I began with a very simple chart, the average runs scored per team from 1980-2013:

It's partially a function of the scaling of the vertical axis, but it's hard to miss the run-up in offensive production and to see almost precisely when it began. There have always been odd years where offense increases with no explanation--1987 was one of those years. Offensive output increased beginning in 1995 for well-documented and discussed reasons, but it must also be remembered that a wave of new stadiums were built that were much more hitter-friendly than those they replaced. Shorter fences and reduced foul territory combined to produce fewer outs, leading to a greater opportunity to score runs. Regardless of the cause, that period is over as run-scoring is down to its lowest point in 30+ years.

This chart expands the time frame to the history of organized baseball:

Accept some of the labels I used for eras as my weak attempts at humor. The "modern" era of baseball is widely considered to have begun in 1901 with the inception of the American League. Prior to that leagues came and went and innovations in the game were rampant (most of this is from The New Bill James' Historical Baseball Abstract):
1. The introduction of gloves
2. Catcher equipment that caused them to move closer to the plate
3. Moving the pitching mound to 60'6"--this happened after the 1894 season, I think
4. Turning the foul ball into a strike (1901 in the NL, 1903 for the AL), which alone was a huge factor in beginning the onset of the Dead Ball Era

This chart has a tendency to smooth out the fluctuations in run scoring in the 20th Century and beyond but the labels do help show the rise and fall of run scoring. Pitching comes and pitching goes and it appears to have come back again beginning around 2007. Why that is will be for others to decide.

These charts generated about as much Twitter chatter as I've ever received without getting retweeted by someone with more credibility (and followers) than me. Since I love attention more as much as anyone, I continued--this chart shows home run incidence since 1901:

There are brief spasms of increases in home runs (1929-1930, 1987), but they're generally short-term. As I already mentioned, the new parks certainly played a role in the increase in home runs that began in 1995 but both runs and home runs are down over 18% since 2000:

Whether this is short-term or indicative of another shift in historical trends is too early to determine, but it has gained momentum since around 2007.

The last chart generated absolutely no interest whatsoever but I'll put up anyway--it shows the incidence of steal attempts in a game (stolen bases and caught stealing) since 1920:

This chart is a little trickier in that running on the base paths is typically inverse to runs scored, i.e., when runs are "easier" to score teams are more content to get runners on base and drive them in. The running game clearly had a renaissance from around 1960-1985 but fell off dramatically in the 1990s. As runs became more difficult to score it appeared that stealing might be making a resurgence around 2010 but 2013 threw a large bucket of cold water on that idea. 2013 very well could be the blip as team speed in general is coming back into fashion, but stealing bases needs to be coupled with the risk of an out, and the work by Tom Tango with the Run Expectancy Matrix (the second table in particular) shows the value of the added base is usually not outweighed by the cost of the out. Look at the teams left in the postseason--Boston was 4th in the majors in stolen bases...the Dodgers 15th, and the Tigers and Cardinals dead last at 29th and 30th.

No sport ever stays still--Robert Griffin III, Colin Kaepernick and Russell Wilson were all the toasts of the NFL in 2012 and are having varying levels of success in 2013. Trends in the NBA come and go (except when LeBron James is playing) and baseball is the same--sometimes hitting rules, sometimes pitching and sometimes there's a pretty good balance between the two. I've written no shortage of posts suggesting that pitching may be on the rise, the question is one of for how long this might be the case.

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