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Medical Care Family SES Access History Vaccination Health Condition Figure 1. A directed acyclic causal graph associating childhood vaccination with a subsequent health condition. (a) Assume that SES is associated with the childhood health condition by a direct pathway in addition to its association through access to medical care. Add this relationship to the causal graph, and determine which variables you should select to control for confounding of the association between vaccination and the health condition. Are there any other sets of variables that could be controlled to remove confounding effects? (b) Assume that access to medical care has no influence on vaccination rates or on the risk of the childhood health condition. Draw a new causal graph reflecting these assumptions, and determine whether any confounding of the association between vaccination and the health condition remains. An investigator chooses to adjust for access to medical care in this scenario. Will their analysis be confounded or unconfounded