Here is an abstract you should look at.
Br J Sports Med. 2014 Mar;48(6):440-7. doi: 10.1136/bjsports-2013-092202. Epub 2013 Jun 13.

Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe: a 1-year prospective cohort study.
And then there is this article we came cross at Runner’s World online. Here is the article “Five things i learned about buying running shoes”.
In all fairness we do not think the article was meant to teach or say much, but we do feel like it robbed 2 minutes of our productive life, at least it was entertaining.
So it is our turn now, let us serve you some real meat.  Here are some loose thoughts on why shoe fit and research has limitations in our opinion, mostly commentary on the first article and why you need to takes its commentary with a grain of salt.
The problem lies in the knowledge base. Most researchers just do not seem to know enough about the foot types , osseous torsions, the kinetic chain, and the like, to do an ALL ENCOMPASSING study. Plus, such a study would be an infinite nightmare. This is where a clinician is needed, to draw upon all of the issues at hand, not just some of the issues.  
For example, in this study, they just looked at arch heights and their determination as to whether the foot was pronating to a degree  (foot-posture index and categorized into highly supinated (n=53), supinated (n=369), neutral (n=1292), pronated (n=122) or highly pronated (n=18).)
No where did they talk about foot types such as the very common forefoot variants of varus and valgus let along their compensated and uncompensated forms. No where were there discussions of tibial or femoral torsion or the possibly necessary foot pronation needs to bring the knee joint back to the sagittal plane. Plus, just because a foot is flat, doesn’t truly mean it is over pronated. It may be flat because of genetics, we have talked about genetic trends here in previous blog posts.  We see plenty of flat competent feet in our clinics. The may appear flat or over pronated , but that is not the case for many people. The FUNCTION must be examined, and this does not come from visual inspection or from gait analysis video. We always say “what you see in someones gait or foot function is often their compensation around other issues, it is not their problem”.
Shawn and Ivo, the gait guys