Exploring Young Adult Social Behaviors and Health Outcomes: Genetic Polymorphisms with Targeted Biochemical Properties as Instrumental Variables

Brandon Wagner, University of North Carolina at Chapel Hill
Guang Guo, University of North Carolina at Chapel Hill

Much work has been devoted to trying to understand causal relationships in social settings. Many different approaches and methods have been applied to address the endogeneity of different research questions. The use of instrumental variables is a relatively underexplored possibility within the sociological literature due to serious methodological difficulties. In this paper, we develop the rationale for using targeted single nucleotide polymorphisms as a source of instrumental variables and provide two systems as practical examples. While the results of one model system highlight the difficulty of finding strong instruments, the other system showcases a valid, strong instrument, allowing estimation of the exogenous effect of an otherwise endogenous independent variable. These results, coupled with continuing changes in the field, suggest a possible future place for thoughtful use of genetic instrumental variables as a method for confronting endogenous social models.