At the risk of making it more complicated than it's worth, you really need multiple indexes. Population and GDP are possible metrics, but they still don't captu

At the risk of making it more complicated than it's worth, you really need multiple indexes. Population and GDP are possible metrics, but they still don't capture everything. If we take universities as an example there's an absolute rank, but then there's also a rank within sub-colleges to tell us that while Harvard is a high ranking university, it's comparatively much more renowned for law than for computer science.