While writing up the wide receiver section for our football magazine the last several years, I've noticed a few things about wideout stats that hadn't initially occurred to me. For starters, it turns out that deep threats as a group average more yards per target than possession receivers.
At first glance, this might seem obvious - they catch longer passes, therefore, they're likely to average more yards per pass thrown. But the length of the pass is to some degree offset by the difficulty in catching it. In other words, yards per target (or receiver efficiency) has two components, only one of which is yards per catch. The other is catch percentage, and possession receivers like Wes Welker and T.J. Houshmandzadeh always crush their deep-threat counterparts by that measure.
Still, it turns out that the yards per catch factor is bigger than the catch percentage one, and so deep threats average more yards per target than possession wideouts. One might think that means teams ought to call more downfield throws considering they give you more bang for the buck. And that would almost certainly be the case if the rules were changed so that one needed 20 yards rather than 10 for a first down. But because short throws often get you first downs, their greater likelihood of success outweighs (in football importance), their lack of overall efficiency. Put differently. if you have a 60 percent chance of getting 12 yards every play, that might be better than a 50 percent chance of getting 16 yards - even though 60 percent of 12 is 7.2, and 50 percent of 16 is 8.0 solely because only 10 yards is needed for a new set of downs. Converting a first down is itself a significant milestone, and so total efficiency isn't everything.
Another way of looking at this is to ask yourself whether you'd rather have an 80 percent chance to win 10 million dollars or a 50 percent chance of winning 25 million. The expected return for the later is far greater, but many (if not most) of us would choose the former because $10 million is enough. Likewise, on 3rd and 9, 10 yards is enough.
So while the yards per target stat is an important one, especially in fantasy, in real life we might want to think about double counting catch percentage and single counting yards per catch to form a new efficiency number. It's similar to people saying OBP should count double and SLG just once to form a better measure than OPS for offensive run production. And the real life stats are relevant in fantasy because teams want to win, and therefore players who contribute to that bottom line should see continued and increased opportunities.