A 2016 meta-analysis found evidence of the Scarr-Rowe effect only in the United States, but no evidence of such an effect in Australia or Western Europe.[1] A 2020 meta-analysis found no evidence that IQ heritability differed across races.[21] Turkheimer et al. (2015) similarly note that the effect has been replicated more in the United States than in other countries, and that even in the United States some studies have failed to replicate it. Based on their analysis of the Louisville Twin Study, they reported weak evidence for the hypothesis that was not statistically significant.[22] Since 2016, research has likewise found contradictory and inconsistent results. In 2017, a twin study with a very large sample of 24,620 twins and 274,786 siblings born and raised in the economically diverse US state of Florida found no evidence of the Scarr-Rowe effect, whereas a different study of 9,012 individuals found evidence for a slight to modest effect in children born in Wisconsin during the 1930s and 1940s