Fran Tarkenton threw 342 touchdowns in his career, but you may be surprised to learn that he didn’t throw more than 25 touchdowns to a single player! He played with John Gilliam from ’72 to ’75, and Gilliam caught 25 touchdowns during those four seasons before signing with Atlanta in 1976.  Tarkenton played with receiver Sammy White during the final three seasons of Tarkenton’s career, from ’76 to ’78, and the duo connected for 24 touchdowns.  And Tarkenton threw 23 touchdowns to Hall of Very Good running back Chuck Foreman.  While with the Giants, Tarkenton also threw 20 touchdowns to Homer Jones; those were the only four players to catch 20 touchdowns from Tarkenton.

A couple of months ago, I discussed the concentration index as a way to measure how concentrated certain statistics are.  We can do that same thing to measure quarterbacks and receivers to see which players had the most varied passing games.  This will be skewed, of course, in favor of quarterbacks who played for multiple teams, but that’s arguably a feature and not a bug.

Below are the results for the quarterbacks with at least 100 touchdown passes:

By this measure, Jim Zorn stands out as the quarterback with the least concentrated passing game.  Steve Largent caught 39% of his touchdowns, the most of any WR1 in this study.  And Sam McCullum caught another 18% of Zorn’s scoring throws, which is why Zorn’s production looks so concentrated here.

I initially ran these numbers to dive into Donovan McNabb’s numbers a bit more. A couple of weeks ago, Adam Harstad went on a McNabb-inspired rant about his poor teammates. And that was true. McNabb doesn’t rank as low as I would have suspected here, though, in part because of Westbrook and in part because McNabb didn’t throw that many touchdowns. Yeah, none of his receivers caught 30 touchdowns, but McNabb did throw “only” 234 touchdowns. Tarkenton, Testaverde, and Favre rank below McNabb, although McNabb had 92% of his touchdowns come with one team (Tarkenton had “only” 70% of his scoring passes come with the Vikings, while Testaverde didn’t have one team account for even 30% of his touchdowns; Favre had 87% of his touchdown passes come with the Packers). But Brady (and Collins, who also split his time among teams) is right with McNabb, too. This doesn’t mean McNabb isn’t underrated, just that his concentration index isn’t as severe as you might have thought.

On the other hand, there’s Young: not only was his production highly concentrated, but it was highlighted among the greatest receiver ever, another Hall of Fame caliber receiver, and a third darn good receiver.