NL Central Rebounds; AL West Chokes

We're back to status quo. The NL Central had faltered for a few days, falling behind the NL East to 3rd place among the divisions, and the AL West had moved from 5th place to 4th over the slumping AL Central.

Neither move lasted more than a week. Today's division rankings are back to their expected levels.

MLB Division Rankings
1 - AL-E - 100,0%
2 - NL-C - 85,7%
3 - NL-E - 77,1%
4 - AL-C - 35,1%
5 - AL-W - 32,0%
6 - NL-W - 0,0%

Measuring quality wins over the past 10 games, the teams in the NL Central have ranked an average of 7th place in the majors while the NL East teams ranked an average of 16th place.

The American League is a bit more complicated. The AL West has scored slightly better than the Central over the past 10 games (an average of 18th place on average versus 18.6th place on average for the AL Central), yet the West has fallen in our rankings. The reason is that when averaging the Baseball Playoffs Now rankings of each team in a division to produce the division's average rating, we use multiple types of averages.

Normal averages do not reflect the general tendency of a certain group of numbers. An arithmetic mean (normal average) can be skewed by either an unusually high or low number in the group, or it could fail to recognize the difference between a group of numbers that are very close in value and a group of numbers very disparate in value.

The latter problem applies to the AL Central - AL West division rankings. The Central's average ranking is 46.89% and the West's average ranking is 47.12%, so on the surface, the West is doing a bit better.

But using a function called the geometric mean, we see vast differences in the two divisions. The Central's geometric mean is 42.17% and the West's geometric mean is 32.82%, because the West's teams are far more spread out in their strengths than the Central's:

AL Central
CHW - 0.7714
CLE - 0.4897
DET - 0.3838
KAN - 0.1754
MIN - 0.5242

AL West
LAA - 0.6142
OAK - 0.7369
SEA - 0.0534
TEX - 0.4806

You will notice that the Central is grouped pretty securely around both 47% and 42%, their arithmetic and geometric means, respectively. But the West has huge differences between the top team(s) and the bottom team, which means that this division on the whole is somewhat weaker than the Central. In other words, the AL Central is better because it has the power to match the West's best teams - yet its weakest link is not nearly as poor as the West's worst.