We'll start what we're terming "active comparisons" (the distinction we'll want to make regarding this will appear a bit further down...) by making a simple "top-level" examination of some global MLB stats from 2011 and 2006.
The folks at "The Book" (and elsewhere) often isolate very small subsets of actual data, sometimes with the idea that these operate at a level of importance well beyond what can actually be demonstrated (their recent look at "called strikes" is a perfect example of this type of shared assumption). This type of analysis is really a "passive comparison" because it assumes a great deal of analytical constants that might or might not hold up under greater scrutiny. We're better off starting at the top level and peeling off the layers of the onion a bit more slowly.
BABIP (the stat that fuels much of the work of the 21st century fielding men) is down only 2%, but its more complete cousin (the one that includes doubles and triples in the TB calcs, and that we've called slugging average on balls in play or SLIP) has moved down a bit more than 4%. That again tracks with a general 2-3 movement between OPS and run scoring changes.
The chart breaks down a few key splits and situations that might just tell us more about the dynamics of the pitcher-hitter duel than umpire adjustments and variations in called strikes. The biggest decline in the overall platoon advantage data is found in lefty batters vs. righty pitchers: this more favorable matchup has fallen a good bit more than is the case for righty hitters against lefty pitchers. (That pattern persists in the left-left/right-right splits.) Lefty hitters seem to be the ones taking it on the chins most of all in the overall context of offensive decline.
In terms of the "count"--the pitch-by-pitch skirmish between batter and pitcher--the biggest change seems to have occurred when batters fall behind 0-1. The 8% drop that occurs here is twice as much as what's happened on the first pitch or after the count starts 1-0.
It should also be noted that the percentage of plate appearances that conclude with the first pitch has also dropped around 8% over the past five years. We'll have a much more detailed look at this effect in our next post, but there are some fascinating historical undercurrents in this area that involve examining the full 24-year data set of pitch-by-pitch info that's currently available to us.
One of the persistent pet theories of neo-sabe analysis is the idea that starters show throw fewer times through the batting order (Mitchell Lichtman is probably the most vocal about this, though Craig Wright got there first). It's interesting enough to warrant some team that not's really going anywhere in 2012 (the Astros come to mind) to give it a try, if only so we might have something to actively evaluate. (It's a bad sign for those in or on the fringes of the "consultancy culture" when these ideas fester for so many years without some kind of trial...makes one wonder just how seriously "outside-the-box" thinking is really taken.) The idea can be actively addressed, however, by looking at inning-by-inning OPS and ERA data.
What we can see is that starters and set-up men led the way in cutting down offense from '06 to '11, gaining more ground than average in the first, second, fifth and eighth innings. However, it's still true that only the closers (appearing almost exclusively in the ninth inning) actually get their ERA and OPS figures significantly below the starters' performance. Set-up men (predominantly eighth inning) seem to have made strides, but the level of improvement isn't quite dramatic enough to signify a wholesale change toward a five-pitcher-per-game model (starter for five, followed by four one-inning specialists).
It's true that to really get inside this issue, we need to break out the inning-by-inning data from the sixth inning on into starter-reliever categories. That would show us just how much difference there is in the their performances, but that's a level of detail not readily available at present. (We'll try to shake it loose as soon as we can, however).
Finally, looking at the K%/2-strike and BB%/3-ball percentages makes us pine to see what those numbers would have looked like in 1968, mostly to see if the BB-rate actually fell below the K-rate. (Probably not, though: we are tracking at the highest level of K/game in baseball history).
Next: a look inside the one-pitch at-bat and how that dynamic has gone through some mind-boggling changes in the past quarter-century. Stay tuned...