"Suppose you want to test the claim

"Pitching is 75% of baseball." If this were true, you would conclude

that the teams with the best pitching would be much more likely to win

the pennant than the teams with the best hitting. However, this isn't

the case. The league leaders in fewest runs allowed (which is both

pitching and fielding) win the pennant about half the time; the league

leaders in runs scored (which includes all of hitting) win just as

often. (Note the definition of offense here: if you measure hitting by

an incomplete measure such as batting average, you would conclude that

pitching is much more important.) Other unreasonable conclusions also

follow; for example, a team with 75% of its value in pitching would

never trade a regular pitcher for a regular hitter. Thus the claim must

be rejected. But if 75% is replaced by a number close to 40%, the

conclusions become reasonable. This is how a sabermetric argument

works."

From: http://www.baseball1.com/bb-data/grabin ... festo.html