I wonder how hard it would be to formalize this claim about mediation in terms of the space of causal DAGs. I haven’t done the work to try it so I’m mostly spitballing.
Informally, I associate mediation with the front-door criteria in causality. So, the usefulness of mediation should reflect that the front-door criterion is empirically easier to satisfy than the back-door (and other) criteria maybe because real causal chains tend to be narrow but long? Thinking about it a bit more, it’s probably more like the min cut of real world causal graphs tend to be relatively small?
I wonder how hard it would be to formalize this claim about mediation in terms of the space of causal DAGs. I haven’t done the work to try it so I’m mostly spitballing.
Informally, I associate mediation with the front-door criteria in causality. So, the usefulness of mediation should reflect that the front-door criterion is empirically easier to satisfy than the back-door (and other) criteria maybe because real causal chains tend to be narrow but long? Thinking about it a bit more, it’s probably more like the min cut of real world causal graphs tend to be relatively small?