The causal effect of parent occupation on child occupation: A multivalued treatment with positivity constraints

To what degree does parent occupation cause a child's occupational attainment? We articulate this causal question in the potential outcomes framework. Empirically, we show that adjustment for only two confounding variables substantially reduces the estimated association between parent and child occupation in a U.S. cohort. Methodologically, we highlight complications that arise when the treatment variable (parent occupation) can take many categorical values. A central methodological hurdle is positivity: some occupations (e.g., lawyer) are simply never held by some parents (e.g., those who did not complete college). We show how to overcome this hurdle by reporting summaries within subgroups that focus attention on the causal quantities that can be credibly estimated. Future research should build on the longstanding tradition of descriptive mobility research to answer causal questions.