All of this analysis is completely and utterly flawed (including US News and all the other commercial rankings). Simply put, none of these analyses consider errors in the weights and inputs. Should quality X be given 10% weight, 15% weight, or 24.78654% weight? Who knows?!
NRC tried to do an honest ranking of PhD programs, taking into account ranges of weights and errors… and what they ended up with frustrated the public who wanted a simple ranking. The NRC rankings gave a range of rankings. For example, a school might have program X ranked in the range 4-28. To the public, that seems absurd that a program might be ranked #4 or #28… but the reality is, it really is hard to tell the difference between similarly ranked programs (well, if you are being honest).
So carry on… but just know that you are just fooling yourself if you think you can measure academic programs in an objective, precise way. It can’t be done. The best you can hope for is very approximate groupings of roughly similarly quality schools. The rest is just measuring how many angels can dance on the head of a pin.