Sounds like this is perhaps related to the counterfactual-consistency statement? In its simple form, that the counterfactual or potential outcome under policy “a” equals the factual observed outcome when you in fact undertake policy “a”, or formally, Y^a = Y when A = a.
No, not quite. Counterfactual consistency is what allows you to link observed and hypothetical data (so it is also extremely important). Counterfactual definiteness is even more basic than that. It basically sets the size of your ontology by allowing you to talk about Y(a) and Y(a’) together, even if we only observe Y under one value of A.
edit: Stephen, I think I realized who you are, please accept my apologies if I seemed to be talking down to you, re: potential outcomes, that was not my intention. My prior is people do not know what potential outcomes are.
edit 2: Good talks by Richard Gill and Jamie Robins at JSM on this:
Sounds like this is perhaps related to the counterfactual-consistency statement? In its simple form, that the counterfactual or potential outcome under policy “a” equals the factual observed outcome when you in fact undertake policy “a”, or formally, Y^a = Y when A = a.
Pearl has a nice (easy) discussion in the journal Epidemiology (http://www.ncbi.nlm.nih.gov/pubmed/20864888).
Is this what you are getting at, or am I missing the point?
No, not quite. Counterfactual consistency is what allows you to link observed and hypothetical data (so it is also extremely important). Counterfactual definiteness is even more basic than that. It basically sets the size of your ontology by allowing you to talk about Y(a) and Y(a’) together, even if we only observe Y under one value of A.
edit: Stephen, I think I realized who you are, please accept my apologies if I seemed to be talking down to you, re: potential outcomes, that was not my intention. My prior is people do not know what potential outcomes are.
edit 2: Good talks by Richard Gill and Jamie Robins at JSM on this:
http://www.amstat.org/meetings/jsm/2015/onlineprogram/ActivityDetails.cfm?SessionID=211222
No offense taken. I am sorry I did not get to see Gill & Robins at JSM. Jamie also talks about some of these issues online back in 2013 at https://www.youtube.com/watch?v=rjcoJ0gC_po