The gang at Football Outsiders has developed a cool new stat, called the Leader Ratio:

Leader ratio is simple: If a player leads the league in a statistic (we'll use rushing yards for the purposes of this article), you divide his total yards by the total yards of the player who came in second. In 1958, when Jim Brown led the league with 1,527 yards, the second-best rusher was Alan Ameche with 791 yards. So that gives Brown a leader ratio of 1.93, which happens to be the best in the history of pro football.

I love stuff like this. There are limitations to this kind of statistic (is a back playing for a run-oriented offense? does he play with a great QB who spreads defenses? etc.) but as these things go this is pretty useful in determining how a back should rank against the rest of the league in a given year.

Switching to baseball for a sec, it's stats like this that lead me to conclude that Babe Ruth was far and away the greatest baseball player of all time, and no argument can be made that he wasn't. There are some years in Ruth's career when he hit more homeruns than any other TEAM!! Stats like that go a long way to helping demonstrate player greatness over time.