WHAT THE LAST FIFTEEN YEARS HAVE DONE TO THE RECORD BOOK

Some years back, for a series in BBBA 1996, I pulled together some data on the "frequency of statistical achievements" for hitters--something that was supposed to run, I think, as part of our "offensive explosion" discussions. It didn't make the cut, but I found it the other day, and realized that if we updated it to 2010 and compared the distributions, we just might find out what the impact of the now-waning "explosion" period had on the record book.

And we might just find a way to adjust some of our perceptions about that period accordingly.

The following counting stats were compiled for 1876-1995 and for 1876-2010: runs scored, hits, doubles, triples, home runs, total bases, runs batted in, bases on balls, extra base hits.

The following derived stats were compiled: batting average, on-base percentage, slugging average, on-base plus slugging, runs creates, isolated power.

These are frequency distributions; that is, the number of times someone has reached a particular number in the statistical categories. Lets use home runs as the example, since it's the "big ticket" item in more senses than one. Looking at the chart, we see that the number of 40+ homer seasons has nearly doubled since 1995 (the ∆ column measures the change as a value comparing the 2010 frequency to 1995's, which was set at 100).

Of course, this chart tells you what you already know: that the home run dominated the past fifteen years and hitters completely rewrote the record book at all thresholds. But you may not have seen the data presented in exactly this way before.

What we'll do now is look at four groupings of these stats based on the amount of change to the frequency distributions that occurred. We are mixing together the counting and the derived stats here, and that mixture will make for an interesting depiction of the shape of the changes that occurred as a result of how the game was played over the past fifteen years.

The low change group, in keeping with what we know as the distinguishing feature of the 1995-2010 time frame--the rise of isolated power as a result of the home run explosion, is not all that surprising: batting average, triples, hits, and runs scored (the distribution of runs scored throughout the batting order has shifted subtly, and has served to dampen the level of change for individual players).

The assault on the hits record, of course, cuts against the grain but is really due to the presence of Ichiro Suzuki, a clear throwback to a type of player and a style of play that was still flourishing in the early 90s. It's interesting how many people, including numbers types who have their ideological subconscious firmly joined to the more uniform style of play as it relates to theories of offense and the concept of "efficiency" as it is now being applied to the game, are fascinated by Ichiro. Perhaps it's because when they watch him,  they sense that there's something about baseball that is otherwise absent from the game.

The upper echelons of the other stats seem impervious to any assault at this point, due to the increasing uniformity of hitting styles over the past fifteen years.

There is a fifth member of the low change group that's a bit surprising, however: on-base percentage. Despite Barry Bonds's rewrite of the OBP record, the overall change profile here is relatively weak. Given that batting average has been deemphasized, it's perhaps not surprising that there are proportionately fewer high-walk, high-batting average types to be found. The shape of the current offensive explosion seems to exclude them.

The moderate change group reflects this lag in OBP, and shows that the offensive explosion in the last fifteen years stemmed a bit more from hitters figuring out how to hit the ball far and get extra bases on their hits. (It seems to be easier to get everyone to do this, hence the increasing uniformity.) The moderate change stats: base on balls, on-base-plus-slugging, and slugging average.

If you think about it, it makes sense that SLG by itself hasn't gone through the roof. High SLG requires high batting average or a massive infusion of extra-base hits as a percentage of total hits. The former drove the records set in the 20s and 30s; the latter drove the overall increase in isolated power that occurred over the past fifteen years, but doesn't necessarily translate into high SLG seasons for individuals. Coupled with the lag in BB, that also tends to dampen the effect on OPS.

The pronounced change group makes for an interesting linkage that could ruffle some feathers in the numbers world. The three stats in this group are runs created, total bases, and runs batted in. Ah, but aren't RBIs supposed to meaningless outside of particular contexts? This is a long-standing ideological canard that's more of an "us vs. them" litmus test for "the cause" than it is a particularly objective look at how RBI have functioned in the game itself. The fact that RBI are linked with two totalizing stats such as total bases and runs created indicate that there are associations between the stats that go deep into the structure of how batting orders work, and why it still makes sense to "concentrate one's fire" in terms of where to bat one's best hitter.

Looking at the data down each threshold, we see that there's a lot of similarity in the pattern of change between total bases and RBI, which is probably due to the mechanics of the batting order, which locks in a certain circumscribed ratio for these stats which is going to behave in a highly stable manner. (In other words, #3-#4-#5 hitters are likeliest to have the most TB and the most RBI, and the highest ratio between RBI and TB.)

Runs created, being a stat that models performance, operates differently and has something of a divergent profile across its thresholds. A good bit of that, of course, is Barry Bonds, and it could be that if we simply removed Bonds from the sample, we'd find that the RC numbers are a lot more similar to the RBI and TB distributions. And wouldn't that be disturbing to the folks who still need to bash RBI!

Finally, the high change group, four stats that should be no particular surprise at this point (no real "mystery guests" here): we are talking about isolated power, extra-base hits, doubles, and home runs.

One of these stats is a bit unlike the others, however, in that the overall shape of its change diverges from the "destroy the top end" approach of the other three. Which is that? It's doubles, where the assault is clearly concentrated at lower thresholds.

The consistency of gain in isolated power is more similar to the home run data than it is to the overall extra-base hit data, which again indicates that home run hitting has driven the shape of offensive upswing over the past fifteen years. Most of the work in rewriting the record book, then, can be seen as the doing of just a few players, with Bonds--the great lightning rod for a "tainted" era--stepping up to the play as combination hero/anti-Christ.

We'll come back and examine this same idea, applied to the fifteen years between 1919 and 1934--a time frame of at least equally significant change to both the game and to its record book--a bit later on.