Just in case you thought the correlation between human capital and economic development was an artifice of the post-socialist world, here is a similar graph (R2=0.4273) for all the world’s countries that have participated in the Math and Science portions of the PISA or TIMMS (8th grade) international standardized student assessments.
The methodology is the same as described in the previous post. As you can see, the relation is every bit as strong at the global level. However, you may point to a few outliers. How to explain them?