I think everybody believes that education matters, at least a little, for the economic prospects of a country. If people don’t have skills, they can’t do things. How can someone be an engineer if they don’t know calculus? What we still don’t know is how important it is, really, and what we can do to improve. I do not have a solution to this, so I will instead address one tiny corner – the datasets we use are kinda just bad, and bad to the point that we will believe false things about the world.
Specifically, in order to convert the achievement tests in Africa to something internationally comparable, we need to make assumptions which are almost certainly not true. The result is that the educational performance of every Francophone African nation is much too high, and that education is more important than we think. Further, countries like India, while performing much worse than the developed world, are not actually on par with sub-Saharan Africa, and it is reasonable to be more optimistic about India’s growth prospects.
The first attempt to try and link “human capital” to growth was Mankiw, Romer, and Weil (1992), who propose adding it as a factor of production in a Solow model, and seeing how much of growth they can attribute it to the variable. (For more detail on the Solow model, see here). They find it is surprisingly effective at explaining growth, although attributing causality is difficult. (Do countries get rich because they school, or do they have school because they are rich?). However, their measure of education was really bad. It’s just the average percentage of the population 15-19 that was in secondary school between 1960 and 1985, which completely misses variation in primary school. So, later, better data sets would use years of education as the variable.