by rburgh » Tue Sep 13, 2011 7:13 pm
Those concerned with OPS+ and ERA+ should be aware that the strat-o-matic model is differential, rather than proportional. Player cards are created based on the differences between their stats and the league stats, rather than the ratio of their stats to the league stats.
So Duffy's OPS of 1.196 in a league with an average SLG of .435 and an average OBP of .379 is .382 better than average. If you give him an OBP 123 points above the 2010 NL, and a SLG 259 points above the 2010 NL, he would have an OPS+ of 203 rather than 172. This would be tied for 43rd with Gehrig 30, Brett 80, Lajoie 04, Sosa 01, and a guy named Dave Orr from 1885. Not too shabby for a guy who played in an era where HR's were rare.