Genetic Markers as Instrumental Variables
Project Team: Professor Carol Propper, Stephanie von Hinke (Bristol), George Davie Smith (Bristol), Debbie Lawlor (Bristol), Frank Windmeijer (Bristol)
The use of genetic markers as instrumental variables (IV) is receiving increasing attention from economists, statisticians, epidemiologists and social scientists. Although IV is commonly used in economics, the appropriate conditions for the use of genetic variants as instruments have not been well deﬁned. The increasing availability of biomedical data, however, makes understanding of these conditions crucial to the successful use of genotypes as instruments. We combine the econometric IV literature with that from genetic epidemiology, and discuss the biological conditions and IV assumptions within the statistical potential outcomes framework. We review this in the context of two illustrative applications.