This tells us how these guys got to their yard totals over the course of limited sample number of games.
A more important thing imo is to determine what these guys are, what type of receiver and then rank them as such.
For example, I see Allen, Hopkins, and Dobson as very similar possession receivers, receivers who will be reliable hitch and catch receivers up to 15 yards--something like Hartline. I like Dobson the best because I think he has the best hands. (I expect him to have the best vertical too from watching games but I do not know this.)
I see Williams and Bailey as intermediate to deep slant receivers primarily--like Jennings.
Swoop and Austin are the the hitch and go threat like Welker, slot types. I like Swoop.
You really have to watch the receivers. IMO, the important things are fluidity, quickness, strength, hands, effort. The metrics, the route tree, the offensive system, the qb, are less important, much less.