Astonishingly Low Results of Cognitive Ability Studies in Developing Countries: Are the Results Credible?

The Global South achieves surprisingly weak results in cognitive competence studies. The values are one to two standard deviations below the established norm. We compare the results of paradigms (student/adult achievement, psychometric intelligence), collections (Becker, Hanushek, Lim, Rindermann, World Bank), and predict outcomes using relevant predictor variables such as education.