League Strength Factor =
(League Total Offense Factor + League Total Defense Factor)/2
League Total Offense Factor = (Your League's Total Offense) / (Average Total Offense for all Leagues of your League type)
League Total Defense Factor = 2 - (Your League's Total Defense) / (Average Total Defense for all Leagues of your League type)
Each League's Total Offense is calculated as follows:
League's Total Offense =
((On Base * Advancement)/Plate Appearances) - (# games * 10 teams in league)
League's Total Defense =
Earned Runs + (.6 * (Fielding Errors + Team Errors))
These numbers are derived by using the following calculations of statistics in your league:
On Base = Hits + Walks + Hit by Pitch - Caught Stealing - Grounded Into Doubleplay