Mark McGwires 1998 season is one that will never be forgotten. To compare it with other great seasons, I used a measure called Bases per Plate Appearance (BPA). It includes the ability to get on base, to hit with power and to add value through baserunning and is calculated as follows:
BPA = (TB + BB + HB + SB - CS - GIDP) / (AB + BB + HB + SF)
Where: BPA=Bases per Plate Appearance
The average major league BPA in 1998 was .463. McGwire had a BPA of .799, the highest ever in the National League. The previous high was .770 by Larry Walker in 1997. Others in the National League top 5 are:
However, the really big offensive seasons have been in the American League by players like Babe Ruth, Ted Williams and Mickey Mantle. These three players account for 11 of the 18 seasons over .750. Ruth has the top two seasons in 1921 and 1920 with BPAs of .863 and .862 respectively. McGwires .799 in 1998 ranks as the third best of all-time ahead of Ruths 1923 and 1927 seasons.
A comparison of the top three seasons is shown below:
McGwire is right there with Ruth in many categories; home runs, RBIs, total bases and walks. The big difference is that singles, doubles and triples are not part of McGwires game. While Ruth was hitting singles, doubles and triples, McGwire was striking out. McGwire had more home runs than singles, fewer doubles than light-hitting teammate John Mabry and hasnt hit a triple since Ronald Reagan was president.
We are clearly in a major offensive era. I expect some big offensive seasons in the next few years but I dont expect to see someone break McGwires home run record in my lifetime.