First off, here's the link to the Baseball America article that does a nice job of assembling the analysis based on statistics over the last three years. They ultimately boil it down to a performance rating designated as PF-R that anyone can use to adjust a player's statistical output, and it's not just based on home runs. It also takes into account that half the games will be played in a player's home park and the other half equally divided among the other stadiums in that league. So one can make a linear correlation by dividing a player's statistics by the PF-R factor.
Some of the results are not surprising and validate generally accepted assumptions we've held about our four primary leagues. The analysis was only done for full season leagues only so that's four teams for the Diamondbacks--Reno in AAA, Mobile in AA, Visalia in High A and South Bend in A. There are 10 leagues analyzed and thus league ratings are out of 10 leagues. The short season leagues were not part of the study.
Reno Aces - AAA Pacific Coast League
League Runs Per Game - 10.69 (2nd out of 10 leagues)
League Hits Per Game - 19.44 (1st)
League Home Runs Per Game - 1.94 (1st)
Team Runs Per Game - 13.32 (3rd out of 16)
Team Hits Per Game - 21.75 (4th out of 16)
PF-R - 1.156 (2nd out of 16)
Summary: Reno plays in a hitter's park in a hitter's league and has one of the highest PF-R factors in all of minor league baseball. The numbers show that performances need to be adjusted by approximately 15%, a huge factor in the world of baseball statistics. Pitchers must hate being sent to the PCL and hitting performances have to be taken with a grain of salt. Hitting .300 in the PCL is no big deal.
Mobile Bay Bears - AA Southern League
League Runs Per Game - 8.85 (8th out of 10 leagues)
League Hits Per Game - 17.06 (8th)
League Home Runs Per Game - 1.36 (7th)
Team Runs Per Game - 8.64 (7th out of 10 teams)
Team Hits Per Game - 17.26 (5th out of 10)
PF-R - .981 (7th out of 10)
Summary: As suspected the Southern League is a pitcher's league, but not disparagingly so. There are a few hitter's parks such as Tennessee, Huntsville and Chatanooga. But Mobile's PF-R comes in a hair under 1.00 so most performances can be taken at face value.
Visalia Rawhide - High A California League
League Runs Per Game - 10.80 (1st out of 10 leagues)
League Hits Per Game - 19.11 (2nd)
League Home Runs Per Game - 1.85 (2nd)
Team Runs Per Game - 10.70 (3rd out of 10 teams)
Team Hits Per Game - 18.55 (3rd out of 10)
PF-R - 1.011 (3rd out of 10)
Summary: The California League rates as the top hitter's league in the minors, but it's almost entirely due to two outliers in High Desert and Lancaster which have PF-R factors of 1.228 and 1.162 respectively. Without those two parks the league might very well be labeled a pitcher's league. In spite of High Desert and Lancaster Visalia's PF-R still comes in at just 1.011, which is essentially flat. So when looking at pitching performances for Visalia one almost has to look at game logs to see how often they are pitching in those two parks. But there are also some extreme pitching parks in the Cal League such as Inland Empire and San Jose which have ridiculously low PF-R factors of 0.894 and 0.922 respectively. A pitcher who through chance pitched more games in San Jose and Inland Empire than Lancaster and High Desert might actually have to be adjusted in reverse. So a high standard deviation among the parks makes the numbers throughout this league a little less reliable than others.
South Bend Silver Hawks - A Midwest League
League Runs Per Game - 9.13 (5th out of 10 leagues)
League Hits Per Game - 16.96 (1st)
League Home Runs Per Game - 1.24 (9th)
Team Runs Per Game - 8.98 (9th out of 16 teams)
Team Hits Per Game - 16.96 (8th out of 16)
PF-R - 1.004 (8th out of 16)
Summary - The Midwest League is in the middle of the pack and many of the parks are quite similar in their performance factors, so it's probably the most fair league of all requiring virtually no statistical adjustments. South Bend's PF-R of 1.004 is almost perfectly flat.