In a recent paper, Clark et al. (2020) analyze the relationship between socio-economic measures and estimates of average cognitive ability (’IQ’) in 140 countries. According to the data presented by the authors, several African, South Asian and Central American countries have an average IQ below 50 (i.e. intellectually disabled, according to DSM diagnostic criteria). Moreover, according to the data presented by the authors, the average cognitive ability of adults in African nations is ∼1.6 standard deviations below the cognitive ability of European adults. These notions are incompatible with psychological science and all conclusions drawn from these data are invalid.