There have been some interesting discussions about how to measure the position of the United States relative to China in the past few months (see here for an earlier take).
One point that has been made a few times, particularly by Beckley, is that we put too much weight on the sheer size of a country. If you took a middling power and added 50 million or so desperately poor, illiterate, starving people, both their GDP and CINC scores (available here, under the National Material Capabilities page of Available Data Sets) would increase dramatically. Yet none of us really believe that such a nation would grow appreciably stronger as a result. It's high time someone proposed a measure that is immune to this criticism.
I doubt it's perfect (in fact, I'm sure it's not), but I'd like to propose such a measure. It focuses exclusively on military components, and so I'm imaginatively calling it M.