The increasing TTO rate and defense
We pointed out on Friday that Colby Rasmus was excelling in the art of the Three True Outcomes. That got us thinking about the TTO in a more general sense. Bill James once noted that the importance of defense is waning; that is, the amount of plays that involve fielders is declining as a percentage of total plays. That trend continues, with about 30% of plate appearances resulting in one of the three true outcomes (home run, walk or strikeout), whereas once only about 5% of plays were TTO, meaning that the defense was involved in 95% of the action. Here’s the graph of baseball’s TTO rate since 1871:
So what has accounted for the many-fold rise in TTO rate? Here’s a breakdown by outcome:
We expected home runs and strikeouts to combine for the uptick, but in reality, the principal thing that has pushed the TTO rate up has been strikeouts. Indeed, the "Two True Outcome" (no strikeouts) rate has been relatively unchanged for more than 100 years:
So it would appear that strikeouts are not necessarily an attendant consequence of hitting home runs. Now whether the increased strikeout rate is because of better pitching or worse hitting is a subject outside the scope of this post, as well as the ken of this writer.
Back to defense for a moment: As Seattle Sports Insider wrote a couple of years ago, "as we get more interested in defense …. ironically, defense continues to affect the game less." Also ironically, defense has gotten better over the same period:
Interestingly, however, defensive efficiency has been declining a bit since a peak period between roughly 1942 and 1972. But the combination of a still relatively high DER and a all-time high in TTO% begs the question: What is the best type of hitter to be in the major leagues today? What will it be in five years?
April 26th, 2010 at 12:11 pm
What’s with the period from about 1896-1910 where there were no strikeouts? Were k’s not kept as an official statistic during that time or were k rates actually that low?
April 26th, 2010 at 12:58 pm
I was about to post the same thing. Clearly there’s a glitch in the statistical reporting. It’s fairly easy to gauge where that line should be from those years, though.
From the early years, home runs were likely so low because parks were bigger and/or didn’t have home run lines boundaries, right? It looks like 1920 was when the first major up-tick happened there.
Likewise, fielding would be much more difficult in a larger park. Decreasing the area needed to be covered would increase the statistical defensive quality. (However, this might be balanced by the decrease in foul areas, where you could get a defensive out without the risk of an error or otherwise statistically notable miss.)
October 14th, 2010 at 2:01 pm
[...] a comment last week, we supposed that the spate of greats was due in large part to an increasing trend in the strikeout rate generally across baseball, inasmuch as fielding-independent pitching rewards pitchers who succeed at the things that they are [...]