So, next time you're looking at a prospect's stats, consider the context in which they were accumulated. Especially at the extremes, ballpark context can make a massive difference in how a player's stats reflect actual performance.
Here's a look at the average number of runs per game for 21 leagues between 2008 and 2012.
But just as there are quirky dimensions and thin-air ballparks across pro ball, the way runs have been scored is also different. Statistically, there were 4.3 runs scored per game in the National League and Rookie-level Gulf Coast League. But while you're likely to see more extra-base hits at a Major League game, a greater percentage of those same 4.3 runs in the GCL have come via walks and errors.
To complement the bar chart above, here's a look at the run environment of those 21 leagues over the same five-year span.
OFFENSIVE STATISTICS BY LEAGUE, 2008-2012
|California||Class A Adv.||5.3||.274||.343||.422||.765||2.5||9.4||.971|
|Carolina||Class A Adv.||4.5||.256||.328||.387||.715||2.0||9.3||.972|
|Florida State||Class A Adv.||4.2||.256||.326||.372||.699||1.7||9.1||.973|
|South Atlantic||Class A||4.6||.257||.327||.380||.707||1.9||9.1||.968|
A greater percentage of hits went for home runs at the highest level, as evidenced by the fact that over the past five years the American and National Leagues have ranked first and tied for second respectively in home run percentage.
Perhaps unsurprisingly, pitcher command has been worse at a younger age and a lower level. Four of the five leagues with the worst non-intentional walk rate were Class A Short-Season or Rookie-level leagues. Similarly, fielding percentage correlated directly with level.
Looking at specific Minor League classifications, there were differences between levels and often significant ones within levels.
At Triple-A, the PCL has been much more of a hitters' league than the International League. This was fueled by a higher batting averages as well as greater walk and home run rates. Stadiums such as the hitter-friendly Isotopes Park (Albuquerque), Aces Ballpark (Reno) and Security Service Field (Colorado Springs) were big contributors to those numbers.
By contrast, the three Double-A leagues were among the most balanced of any classification. Separated by just 0.2 runs per game, the Eastern, Southern and Texas Leagues sported similar batting averages, on-base percentages and slugging percentages.
At the other end of the spectrum, Class A Advanced remained one of the most unbalanced levels in professional baseball as the California League continued to live up to its reputation as a hitters' haven. Stats across the board (batting average, OBP, OPS, walks and home run rate) were higher than in the Carolina League -- generally a neutral environment -- and the Florida State League -- a notorious pitchers league which boasted the fewest runs/game and the only full-season league with a five-year OPS below .700.
Further down the chain stand the two evenly balanced, mostly neutral Class A leagues and a pair of short-season leagues which featured more walks, more errors and fewer homers.
At the lowest level -- Rookie ball -- were extreme hitters environments (Pioneer and Arizona Leagues) and stingy pitchers leagues (Gulf Coast and Dominican Summer Leagues). The GCL and DSL featured the two lowest five-year batting averages and home run rates as well as the two highest walk rates and fielding percentages.
Here's an in-depth look at the park factors for each of the full-season stadiums since 2010. Where a club has relocated or changed leagues, two parks between the three years were listed. The table looked at three counting stats -- runs, home runs and hits -- and used a formula to help compare one park from another.
((Runs scored at home + runs allowed at home)/(Home games)) / ((Runs scored on the road + runs allowed on the road)/(Road games))