More home runs are struck in the two Triple-A leagues than at any lower classification. The high Class A California League enjoyed a razor-thin advantage over the International in terms of extra bases per at-bat—or isolated power—but generally speaking, one can expect to see the most extra-base hits per capita at the Triple-A level.

But bubbling below the surface, we find the continuation of recent trends at Double-A and at both low and high Class A. More detail follow the chart. Brush up on last year's minor league averages here.

League context is crucial to the process of ranking prospects. So as you digest our various league Top 20 Prospects lists, you can consult the chart below to see how players compare with the league averages.

• R/9 scales runs scored to nine innings, making no distinction between earned and unearned runs.
• The BB and SO columns figure walks and strikeouts as a percentage of plate appearances. Walks do not include intentional passes.
• Isolated power (ISO) is the difference between slugging and average, separating extra bases and weighing them per at-bat.
• Balls in play average (BIP) figures the rate at which struck baseballs—excluding home runs—evade defenses and are scored as hits.
• The average number of home runs per team and runs scored per team are represented by HR and RUNS.

Double-A
In terms of power output, the Eastern League has kept pace with (and even surpassed) the Texas League in the past two seasons. The EL out-slugged and out-homered TL this season after nearly matching the TL last season. In both seasons, the EL has produced a higher rate of isolated power. This seems to defy common sense, what with the TL's reputation for offense and Northwest Arkansas' crazy power production at home this season.

High Class A
Nowhere is the difference in league context so stark as high Class A, where California and Florida State league players compete in such disparate run-scoring environments that they might as well be playing in different galaxies. Cal League teams outscored their Florida State counterparts by one full run per nine innings. The average Cal team hit 78 percent more home runs and scored 26 percent more runs than the average FSL squad. In fact, the FSL ranked dead last among full-season leagues in average, slugging, runs per nine innings, isolated power and both home runs and runs scored per team. The Cal League ranked second to the Pacific Coast League in every one of those categories, save for homers per team, where the International League held a slim advantage.

Low Class A
The tide is turning in low Class A, where the Midwest League featured more offense than the South Atlantic for the second straight season. In fact, with the annexation of the Bowling Green and Lake County franchises this season, the MWL widened the offensive gap by scoring about four percent more runs per nine innings when compared with last year. The SAL tried to keep pace but only saw about three percent more runs than last year.

In the short-season leagues, smaller sample sizes and greener players make for uneven results from year to year. But one thing remains constant: the Pioneer League is the highest-scoring environment in baseball. Put it this way, the PL's Orem Owlz (81) and Ogden Raptors (79) would have ranked second and fourth, respectively, in the Florida State League in team home runs . . . in about half the number of games.

Both Utah cities have Salt Lake City as an epicenter—Ogden is about 35 miles to the north and Orem is about 39 miles to the south.