I think with a file one can make a very coarse edge that is not necessarily sharp. A very sharp filed edge if done with the Hill method if very sharp before the serration is done will be that much of a keener edge than one that is not so sharp. I put a very light serration on shaving sharp single bevel heads and we are getting great results with them. however, not all files give the type of serration that I look for. The corner of the file has to be very sharp for it to work. If you look at each serration as if it were a tiny individual cutting surface, it would show to be extremely sharp. Plus, if a hard tendon or bone is contacted it makes sense to me that the blade would retain more of a cutting edge and possibly stay sharp in a back quiver longer. Animals are not a consistent medium nor are all broadheads equal. For a time and my son still prefers to use a raised burr done with a very fine diamond steel. The broadhead is shaving sharp under that burr, but the burr is a finer edge than that. I am always surprised by how much of that burr stays in tack after passing through a deer. I am not trying to disprove the findings of the Dr. in anyway, it is just that have found that certain modifications seem to work for us very well and it is perhaps a bit of a novelty and fun to find that our forefathers had somethings right as well. I keep thinking here about the primitive fellow that buried an obsidian tipped cedar to the feathers on a canadian moose with a slower than average osage flat limb, the obsidian point certainly was not razor smooth unless one looks real close at the tiny chipped dimples along the edge, which were probably sharper than razor sharp. The last deer I shot was with a shaving sharp broadhead that neglected to put the serration on, I only ever have two serrated broadheads with me on any given day and I lost both of them shooting at a coyote earlier that day. I cannot say one way or the other that I had an advantage for the rather short blood trail to the deer.