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A couple of weeks ago, I talked about the media uprising concerning the
number of home runs being hit. At the time, there was a growing clamor that
"something" had to be done, with the two most-common remedies
bandied about being altering the baseball and raising the mound.

What I believed, and still do, was that the increased offense wasn’t as bad
a thing as the mainstream media would have you believe, and that three
weeks in April were too small a sample on which to build a case, anyway.
Yes, this is a good hitters’ era, but panicking because the Cardinals were
having a good month was a bit premature.

A few more weeks have passed, and with some of the furor having died down,
I wanted to revisit my own dog in this fight, the changed strike zone. I
firmly believe that the simplest and least-intrusive method of tweaking the
balance between hitters and pitchers is to find some way of calling a
reasonable strike zone.

The zone called by most umpires appears to be far too small vertically and
has been shrinking for some time. In general, it extends roughly from just
above the knees to somewhere between the belt and the bottom of the
ribcage. While there is also a trend towards calling a strike zone wider
than home plate, especially on the outside part of the zone, there isn’t
any consistency in doing so from umpire to umpire.

To me, there’s a clear line between a smaller vertical strike zone and
increased offense. Obviously, a smaller target is harder to hit, leading to
more balls, more hitters’ counts and more walks. Taking away both the high
and the low strike lets hitters focus on a smaller area, one that
corresponds more closely with their "wheelhouse" than the book
strike zone.

But is any of this happening? Does it show up in the statistics? Just as a
starting point, I looked at the two leagues’ walk and strikeout rates and
strikeout-to-walk ratios since 1996:

League     K/9   BB/9   K/BB

NL 2000 6.60 4.07 1.62 NL 1999 6.67 3.74 1.79 NL 1998 6.76 3.37 2.00 NL 1997 6.81 3.42 1.99 NL 1996 6.77 3.33 2.03

AL 2000 6.23 3.58 1.74 AL 1999 6.26 3.72 1.68 AL 1998 6.43 3.45 1.87 AL 1997 6.51 3.55 1.84 AL 1996 6.24 3.81 1.64

This year’s data is through Tuesday.

The American League is all over the place, with a decline in walks and a
jump in strikeouts in 1997 and 1998, followed by a regression in 1999. I
can’t conclude anything based on this other than that Roger Clemens
was really good in 1997 and 1998.

In the National League, though, there is a demarcation between the 1998 and
1999 seasons. The league walk rate jumped 11%, with a corresponding decline
in strikeout-to-walk ratio. So far this season, the league walk rate is up
another 9%, for a jump of 21% in two seasons.

There are some problems with this quick and dirty study:

  1. Thanks to Bud Selig and his long nights in the lab, we’re not dealing
    with stable data sets. Baseball expanded in 1998, and the Milwaukee Brewers
    moved from the American League to the National League, so the changes from
    1997 to 1998 may be masked somewhat by that. Additionally, the parks have
    been changing almost constantly during this time, and that may be clouding
    the data.

  2. I haven’t accounted for intentional walks. I don’t know what impact, if
    any, doing so would have.

  3. The 2000 data is based on just six weeks of baseball.

I’m not presenting this as a final verdict. There are a lot of ways to look
at this, and I don’t pretend this is exhaustive. But when a league’s walk
rate jumps this much in just two years, something is fishy. And with the
strike zone at the heart of other issues, it seems to me that this is a
good starting point for further analysis.

Joe Sheehan can be reached at jsheehan@baseballprospectus.com.