All players have a rating of the form AeB. A is the range rating at that position (5 is best, 1 is worst). B is the error rating. This rating is a percentage indicating how this player's error rate compares to the average fielder at his position in the era in which he played. A rating of 100 means the player is average -- that is, he makes 100% of the errors expected of someone at that position. A player who makes only 50% as many errors as his peers is rated 50. Someone who makes twice as many errors as his peers is rated 200.