Thailand has a population of over 64 million people, which is comparable to the United Kingdom or France. It is the world’s 21st most populous country.
IQ and the Wealth of Nations (2002) and IQ and Global Inequality (2006) both assign Thailand an IQ of 91 based on one clinical trial from 1989. Lynn and Vanhanen (2012, p. 417) add two more studies that push their estimate down to 88. Some of their numbers are reported inaccurately and these books overlook larger, higher quality, and more recent intelligence test studies for this nation. In particular—as I noted on Gene Expression almost a decade ago—the government of Thailand has implemented broad national IQ surveys, which have been reported in relation to U.S. and U.K. test norms.
In this post I review almost 50 studies of intelligence and scholastic achievement for the nation of Thailand. Many representative studies since the 1990s give conflicting results, making a solid estimate of Thailand’s IQ a difficult task.