We study the effect of birth weight on long-run outcomes, including permanent income, income across various stages of the lifecycle, education, social benefits take-up, and adult mortality. For this purpose, we have linked a unique dataset on nearly all Swedish twins born between 1926- 1958,...

How schooling affects cognitive skills is a fundamental question for studies of human capital and labor markets. While scores on cognitive ability tests are positively associated with schooling, it has proven difficult to ascertain whether this relationship is causal. Moreover, the effect of...