RESEARCH QUARTERLY

Figure 1 reveals that players’ names are sometimes included in
Who’s Who in Baseball when the players are less than 20 years of age.
And a few individuals are included in this very select compilation when
they are past 40 years of age. However, the 28-year-olds (this means
players between their 28th and their 29th birthdays) comprise the
largest single age group. And the three age groups, 27, 28, and 29
inclusive, stand distinctly above the others in the extent to which they
participate in major league baseball.* It should be realized, of course,
that the foregoing statement implies that general baseball proficiency
is probably greatest within the three above-mentioned age groups.
With the available data, it would easily be possible to determine
whether there exist statistically significant age differences with respect
to such separate performances as batting, fielding, base-stealing, and so
forth. The fact that such age differences may exist will be more fully
realized when the reader examines Figure 2 which sets forth data for
1,666 baseball pitcher-years. The data for Figure 2 were obtained from
Who’s Who in Baseball in a manner analogous to that employed for
obtaining the data for Figure 1. The following computations reveal the
very select nature of the pitcher group:

22 = Number of editions of Who’s Who that were canvassed.
1,666 = Total number of pitcher-years.
22 ) 1,666
75.727 = Number of pitcher-years for each of the 22 seasons.
16 = Number of clubs in the two major leagues.
16 ) 75.727
4.733 = Average number of pitchers included in Who’s Who each

season from each of the 16 major league clubs.

The above computation reveals that, in their annual editions of
Who’s Who in Baseball, the editors ordinarily include an average of
slightly less than five pitchers from each of the sixteen major league
clubs. Figure 2 reveals that, of the pitchers whose names were listed in
Who’s Who in Baseball for a period of 22 years, the 27-year-olds com-
prise the largest single age group. The modal age for the pitchers is
thus one year younger than the modal age for players other than
pitchers.

Figures 1 and 2 make no allowance for the fact that there is always
a larger number of young than of older men in the population at large.

*In constructing the graphs that accompany this article, the data for each of them
were first reduced to a comparable basis by the following procedure: The peak of each
statistical distribution was arbitrarily assigned a value of too per cent and the other
numerals within the same statistical distribution were assigned proportionate percentage
values. For example, in Figure 1, the peak of the distribution occurred at age 28. At
this latter age the number of baseball player-years was 322. In Figure 1 at age 28 the
figure 322 is plotted therefore as 100 per cent. At age 30 the number of player-years
was 252. This figure is equivalent to 78 per cent of the maximum (78 per cent of 322)
and in Figure 1 the numeral 252 is plotted therefore as 78 per cent. The foregoing
method of plotting should be borne in mind when studying the graphs.

+ This might not be true for a country which has had a declining birth rate for
many years.