8.6 Using Paths to Test the DAG
How do we check to see if our DAG is large enough?
- Placebo test: finding a relationship that your causal diagram says should be zero, and checking whether it’s actually zero.
Placebo Test Procedure
Beyond the treatment and outcome, choose two nodes A and B
- List all of the paths between A and B.
- Do what you need to do to make sure they’re all Closed.
- If A and B are still related to each other (by observational data), that means there must be some other path you didn’t account for.