Hello Chris,
I also agree with you on what the predictor variable (race/ethnicity) is actually measuring. Clearly defining this in key, as it determines the role of SES as a confounder/mediator/effect modifier in the association. I think your proposed study is interesting, and I am wondering what specific birth outcomes you are interested in. If you were to draw out the DAG, prenatal care engagement could be considered a mediator in your model.
I also agree with you on what the predictor variable (race/ethnicity) is actually measuring. Clearly defining this in key, as it determines the role of SES as a confounder/mediator/effect modifier in the association. I think your proposed study is interesting, and I am wondering what specific birth outcomes you are interested in. If you were to draw out the DAG, prenatal care engagement could be considered a mediator in your model.