I agree. It sounds impressive but it penalizes production in many cases. First downs, plays after penalties, sideline routes, etc. Often are designed for a completion that falls short of a first down. Many times it is wise to take what the defense gives you rather than to force a longer throw. Those things work against that stat.
It's going to be an extension of yards per catch. If you're averaging 13 yards per catch then obviously a large percentage of your catches will be first downs.
This also makes it apples-to-oranges when you're looking at a perimeter receiver versus a slot receiver. Perimeter receivers and slot receivers have slightly different yards per ATTEMPT but much more widely variant yards per CATCH and catch percentages. Slot receivers catch a higher percentage of the balls thrown to them, which is not reflected in a 1st down percentage number at all, but in turn they have a lower yards per completion which absolutely DOES reflect in the 1st down percentage. A guy with 11 yards per completion (about normal for a slot receiver) is going to have a much lower 1st down percentage than a guy with a 13 yards per completion average (more normal for the perimeter). But that doesn't tell you how valuable one is versus the other. The guy in the slot could be averaging 9 or 10 yards per attempt while the guy on the perimeter could be averaging only 6 yards per attempt, and none of that would reflect in the 1st down percentage.
Something I noticed about Brandon Gibson in 2012 was that he wasn't getting open very often, but eerily when he was getting open Sam Bradford found him. Two stats that I personally like to pay attention to in a receiver are yards per attempt and yards per route. They're correlated, but they can also vary and the variance can help support the film observations. Brandon Gibson's yards per attempt figure in 2012 was at 9.2, which is good. Not great, but solid. However, his yards per route were only at 1.47 which is really below average. When you see this kind of discrepancy, you have to look at the film. Sometimes you see the receiver getting open a lot and your conclusion ends up that he's got a low yards per snap because the quarterback just isn't finding him. I default to this assumption more often than not until I get a chance to look at the film.
But when I looked at Gibson's film I wasn't happy at all with how often he was getting open or creating separation. I came to think the reason for the discrepancy is because he's not getting open very often. When he does, and the quarterback threw it, he was on target with a lot of his throws and the receiver reliably caught the football. For instance if you go back to 2008 with Chad Pennington throwing the ball in Miami, even Ted Ginn managed an 8.3 yards per attempt figure, whereas career-wise Ginn is more like a 6.0 kind of player (poor). He wasn't necessarily open that often but when he was, Pennington found him and got the football to him accurately. Gibson's yards per attempt leading into 2012 were 5.5 in 2009, 7.2 in 2010 and 6.6 in 2011...about 6.5 yards per attempt over the period. No doubt he improved as a football player in his fourth season and that probably accounts for some of the improvement, but when I watch the film and see him not getting open very often and then I look at the yards per route, it makes me think a good part of that sudden spike was due to a combination of Sam Bradford's improvement and some randomness owing to sample size.
Bottom line, I watched a lot of film on the guy and wasn't all that impressed. Dress it up all you want, comes down to that.
