IQ and Global Inequality - National IQ and QHC Values

National IQ and QHC Values

Lynn and Vanhanen base their analysis on data gathered from a literature review. They selected IQ data from studies which covered 113 nations. For another 79 nations, they estimated the mean IQs on the basis of the arithmetic means of the measured IQs of neighboring countries. They justify this method of estimation by pointing out that the correlation between the estimated national IQs they reported in IQ and the Wealth of Nations and the measured national IQs since obtained is very high (0.913). In the chart below, these estimates have been marked with an asterisk (*). The chart also includes the measured and estimated IQs from IQ and the Wealth of Nations.

Lynn and Vanhanen calculated the national IQs in relation to a British mean of 100, with a standard deviation of 15. They adjusted all test results to account for the Flynn effect: adjustments were 2 points per decade for Raven's Progressive Matrices and 3 points per decade for all other types of tests. When two IQ studies were used from one country, their mean was calculated, whereas when three or more were available, the median was used. Lynn and Vanhanen recommend the provision of iodine and other micronutrients as a way to increase cognitive functioning in the Third World.