Take the Money and Runs

There's a report that the scoring is down to the lowest level since 1993. ESPN attributes it to pitchers catching up with hitters:

Forget the long ball.

After a decade of record-setting bashing in baseball, pitchers finally are starting to catch up with hitters.

First, I have to say that this is an issue that is by no means as facile as the media would lead you to believe.

Second, I have a chart, what else? It lists the total runs and home runs per game with their percent change by year since the dawn of the expansion era. There is also the average and standard deviation for each of the percent change:

Year   R/G   Diff  HR/G   Diff
1960  8.63  -1.58% 1.72  -5.27%
1961  9.05   4.90% 1.91  10.89%
1962  8.92  -1.43% 1.85  -3.03%
1963  7.89 -11.52% 1.67  -9.79%
1964  8.07   2.25% 1.70   1.71%
1965  7.98  -1.17% 1.66  -2.50%
1966  7.99   0.14% 1.70   2.55%
1967  7.54  -5.64% 1.42 -16.45%
1968  6.84  -9.30% 1.23 -13.49%
1969  8.14  19.14% 1.60  30.55%
1970  8.68   6.61% 1.76  10.05%
1971  7.78 -10.43% 1.48 -16.25%
1972  7.37  -5.21% 1.36  -7.73%
1973  8.43  14.32% 1.60  17.12%
1974  8.25  -2.12% 1.36 -14.69%
1975  8.43   2.13% 1.40   2.43%
1976  7.99  -5.17% 1.15 -17.37%
1977  8.94  11.91% 1.73  50.33%
1978  8.21  -8.21% 1.41 -18.84%
1979  8.92   8.63% 1.64  16.30%
1980  8.58  -3.80% 1.47 -10.33%
1981  8.00  -6.76% 1.28 -12.88%
1982  8.60   7.49% 1.60  25.52%
1983  8.62   0.24% 1.57  -2.40%
1984  8.51  -1.18% 1.55  -1.12%
1985  8.66   1.74% 1.71  10.66%
1986  8.82   1.81% 1.81   5.86%
1987  9.45   7.11% 2.12  16.80%
1988  8.28 -12.38% 1.51 -28.50%
1989  8.26  -0.14% 1.46  -3.33%
1990  8.51   3.00% 1.58   7.64%
1991  8.62   1.21% 1.61   2.04%
1992  8.23  -4.43% 1.44 -10.28%
1993  9.20  11.67% 1.78  23.12%
1994  9.85   7.09% 2.07  16.33%
1995  9.69  -1.55% 2.02  -2.08%
1996 10.06   3.77% 2.19   8.06%
1997  9.53  -5.24% 2.05  -6.34%
1998  9.57   0.38% 2.08   1.58%
1999 10.17   6.27% 2.28   9.45%
2000 10.28   1.09% 2.34   2.94%
2001  9.55  -7.10% 2.25  -4.13%
2002  9.27  -2.91% 2.09  -7.03%
Avg          0.36%        1.35%
Std Dev      6.97%       14.96%

Do you notice how wildly fluctuating this figures are? The standard deviation is a 7% swing for runs and a 15% one for homers. The dropoffs in the last few years are miniscule compared to a number in the past: from -12% to +19% in runs and from -28.5% to +50 in home runs. So to say that this shows that pitchers have caught up with hitters is ludicrous. Were they catching up with and falling behind each other constantly in the last 40+ years? Besides, the 1993-2000 numbers are much higher than the previously established levels.

There are a number of factors that may be responsible for the slight decrease in runs and home runs the last few years. First, there have been a number of new parks that were in the 1990s. There were twelve since 1990 as a matter of fact, about one a year, plus four other parks used by expansion teams. Most of those ballparks are hitters' parks, and the influx of so many (about half of all stadiums) at once could have disadvantaged the pitchers. There were no new ballparks in 2002.

One other factor that has loomed large in the 1990s is expansion. The two closest rounds of expansion ever were in the '90s (1993 and 1998). You'll notice that all but the 1962 expansion have been accompanied by scoring increases. After a couple of years the trend has been reversed and scoring has returned to its previous levels. The 1990s saw this after the 1993 expansion, but the correction was halted by the 1998 expansion. Baseball is just starting to get back to its previous levels. Why does scoring increase after expansion? The prevailing theory is that pitchers take a little more time to mature than hitters. When there is a large influx of talent, such as when the majors expand, the batters that fill those new positions tend to be better prepared than do the pitchers. Of course, after the 1961-62 expansion analysts were saying the opposite, that scoring was down because there weren't enough good hitters to fill the roles. The theory as to why scoring goes down a few years after expansion is that pitching resources are at a premium and it takes a few seasons for them to be more evenly distributed among the teams.

If you want to reduce that to pitchers catching up with batters than I guess the media are correct. But there are a myriad of other factors (training, conditioning, nutrition, organizational approach, equipment changes, etc.) that come into play. Besides the slight fluctuations in 2001-'02 are not large in the scheme of baseball history.