Writing in the Economic Journal, Astrid Oline Ervik said that the book may be "thought provoking", but there is nothing that economists can learn from it. She criticized the book's authors for not establishing cross country comparability and reliability of IQ scores, for relying on simple bivariate correlations, for not considering or controlling for other hypotheses, and for confusing correlation with causation. Ervik stated, "The arguments put forward in the book to justify such comparisons [between the average IQ in different countries and their GDP] seem at best vague and unconvincing. At worst, passages in the book appear to be biased and unscientific...The authors fail to present convincing evidence and appear to jump to conclusions."
