A pre-modern, medievalish society that nevertheless used a lot of selection/testing was China - I am thinking about the famous mandarin exams. Does this seem to have had any positive effect on China compared to other similar societies? I.e. is this even like that it is a big factor in the general outcomes of 2015 West vs. 1515 West? Comparing old China with similar medievalish but not selectionist (but inheritance based) societies would be useful for isolating this factor, right?

Here are two posts going into detail about the economic history of China. (HT: Michael Anissimov)