Just like the Bayesian network shown above. I want to identify the average treatment effect(ATE) from Smoking to Lung Cancer. If Genetics is observable, I can easily identify the ATE with Pearl's backdoor adjustment.
But now, the Genetics is unobservable. As shown in the network, there's no front-door path between Smoking to Lung Cancer. So how to identify the causal effect?
- All nodes can be observed except the Genetics.
- There're more nodes, but those nodes aren't in any paths between Smoking and Lung_Cancer. The whole network is shown below.