Thomas Piketty’s Capital in the Twenty-First Century is the most widely discussed work of economics in recent history, selling millions of copies in dozens of languages. But are its analyses of inequality and economic growth on target? Where should researchers go from here in exploring the...

This paper discusses various methods for assessing group differences in academic achievement using only the ordinal content of achievement test scores. Researchers and policymakers frequently draw conclusions about achievement differences between various populations using methods that rely on...