With controlled experimentation, one can be almost certain that the effect measured is due to the variable modified. It doesn’t matter if you have a correct graph of the confounding factors, because you balance them against each other.
What you are doing is measuring the combined strength of all chains of the type A->?->Y
Even in randomized trials you need to worry about assumptions. For example, you have to worry that your samples represent the general population. You have to worry that the actual random assignment with the people you have in your study well approximated the ideal random assignment in an infinite population. You then have to worry about modeling assumptions if you are doing statistical modeling on top of that. It is true you don’t need assumptions that link observational and interventional quantities if you randomize.
“What you are doing is measuring the combined strength of all chains of the type A->?->Y”
If the graph is as I described that’s what you want (e.g. the causal effect, e.g. the variation in Y under randomizing A).
I don’t do random assignment. I divide the sample set into two or more groups that are as close to identical as possible, including their prior variation along A. Figuring out if one split is closer than a different one is nontrivial.
The only random decision is which group gets which A.
With controlled experimentation, one can be almost certain that the effect measured is due to the variable modified. It doesn’t matter if you have a correct graph of the confounding factors, because you balance them against each other.
What you are doing is measuring the combined strength of all chains of the type A->?->Y
Even in randomized trials you need to worry about assumptions. For example, you have to worry that your samples represent the general population. You have to worry that the actual random assignment with the people you have in your study well approximated the ideal random assignment in an infinite population. You then have to worry about modeling assumptions if you are doing statistical modeling on top of that. It is true you don’t need assumptions that link observational and interventional quantities if you randomize.
“What you are doing is measuring the combined strength of all chains of the type A->?->Y”
If the graph is as I described that’s what you want (e.g. the causal effect, e.g. the variation in Y under randomizing A).
I don’t do random assignment. I divide the sample set into two or more groups that are as close to identical as possible, including their prior variation along A. Figuring out if one split is closer than a different one is nontrivial.
The only random decision is which group gets which A.