Although some of the more equal countries – such as Norway, Sweden and Finland – have small populations and perform well, there are also small countries like Singapore and Portugal which do particularly badly. And the two countries in our data with the largest populations are the USA and Japan which lie at opposite ends of the inequality spectrum. If you control for population size, the correlations measuring how closely related outcomes are to inequality become even stronger.
Some people wonder whether measures of income inequality are actually biased by population size – making countries with large populations appear more unequal. However, measures of income inequality are all designed to be unaffected by population size.