On the Interpretation of do(x)do(x)

• Main Author: Pearl Judea
• Format: Article
• Language: English
• Published: De Gruyter 2019-04-01
• Series: Journal of Causal Inference
• Subjects: manipulability; causal effects; interventions; testability; reinforcement learning
• Online Access: https://doi.org/10.1515/jci-2019-2002
• ISSN: 2193-3677; 2193-3685

This paper provides empirical interpretation of the do(x)do(x) operator when applied to non-manipulable variables such as race, obesity, or cholesterol level. We view do(x)do(x) as an ideal intervention that provides valuable information on the effects of manipulable variables and is thus empirically testable. We draw parallels between this interpretation and ways of enabling machines to learn effects of untried actions from those tried. We end with the conclusion that researchers need not distinguish manipulable from non-manipulable variables; both types are equally eligible to receive the do(x)do(x) operator and to produce useful information for decision makers.