Causal variables that don't affect any subsequent variables should have a variance of zero. The researchers reconstruct the ...

Despite the observed associations, the genetic analyses found no evidence of a causal relationship between cannabis use and brain structure or function. This indicates that the observed ...

Andrews, Isaiah, Nano Barahona, Matthew Gentzkow, Ashesh Rambachan, and Jesse M. Shapiro. "Causal Interpretation of Structural IV Estimands." NBER Working Paper ...