Working Paper No. 806

The Co-twin Methodology and Returns to Schooling – Testing a Critical Assumption

Published: August 24, 2009Pages: 37Keywords: Returns to Schooling; Twins;, Equal Ability AssumptionJEL-codes: I21; J24
Published version

The Co-twin Methodology and Returns to Schooling – Testing a Critical Assumption Örjan Sandewall, David Cesarini and Magnus Johannesson

Twins-based estimates of the return to schooling feature prominently in the labor economics literature. The validity of such estimates hinges critically on the assumption that within-pair variation in schooling is explained by factors which are unrelated to wage earning ability. This paper develops a framework for testing this assumption, and finds, using a unique dataset of monozygotic twins, strong evidence against it. Di¤erences in adolescent IQ test scores predict within-pair variation in educational attainment, and including IQ in the wage equation causes within-pair point estimates for the returns to schooling to decline significantly. Our results thus cast doubt on the validity of estimates derived from the co-twin literature. 

Sick of Inequality?

An Introduction to the Relationship between Inequality and Health

Sick of Inequality.jpg

In this book Andreas Bergh, Therese Nilsson, IFN and Lund University, and Daniel Waldenström, IFN and Paris School of Economics, France, review the latest research on the relationship between inequality and health. What does inequality mean for our health? Does increasing income inequality affect outcomes such as obesity, life expectancy and subjective well-being?


Seminars organized by IFN


To present ongoing research informal brown-bag seminars are held on Mondays at 11:30 am. This is an opportunity for IFN researchers to test ideas and results.

Academically oriented seminars are most of the time held on Wednesdays at 10 am. At these events researchers from IFN and other institutions present their research.

In addition, IFN organizes seminars open to the public. Topics for these are derived from the IFN research.

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