Mays, Aaron lgBA v. NL BA per season.

Willie Mays and Hank Aaron each have different lgBA from the overall common sense National League (NL) batting average (BA), which is simply all hits divided by all at bats.

As mentioned in recent posts: "baseball-reference.com definition of lgBA: a league average (non-pitcher) would have had in the same park(s)."

We can sort of negate the inclusion of pitchers in the common sense BA by comparing lgBA of both Mays and Aaron to the NL BA.  (NL BA - Mays lgBA) v. (NL BA - Aaron lgBA):



Year NL-Mays NL-Aaron
1954 -0.010 -0.002
1955 -0.008 -0.002
1956 -0.007 -0.001
1957 -0.009 0.000
1958 -0.005 0.002
1959 -0.007 0.001
1960 -0.001 0.001
1961 -0.003 0.002
1962 -0.008 -0.005
1963 -0.008 -0.008
1964 -0.012 -0.010
1965 -0.013 -0.009
1966 -0.013 -0.012
1967 -0.009 -0.008
1968 -0.010 -0.010
1969 -0.008 -0.011
1970 -0.008 -0.015
1971 -0.007 -0.015
1972 -0.006 -0.019
1973 -0.006 -0.018

Let's look at 1954.
lgBA Mays: .275
lgBA Aaron: .267
NL BA (including pitchers): .265

My reason for getting into this was to determine the percent above the league average for various rates, in this case, the simple, innocuous, venerable batting average.  In 1954 Mays led the NL with .345; Aaron in his rookie season batted .280.

Mays Aaron
BA 0.345 0.280
lgBA 0.275 0.267
NL 0.265 0.265
% above lgBA 25.45% 4.87%
% above NL 30.19% 5.66%

What the heck?

But suppose they both had the same BA, let's say .300.
Mays Aaron
BA 0.300 0.300
lgBA 0.275 0.267
NL 0.265 0.265
% above lgBA 9.09% 12.36%
% above NL 13.21% 13.21%

Now the percent above lgBA difference is clear and significant:
Mays 9.09%
Aaron 12.36%

So what the heck?  It's freakin' BA!  Simple, right?  What the heck?  I can't even play with BA and have a little fun, maybe gain some insight?  Geez!