On Searching for Generalized Instrumental Variables
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چکیده
function Find-Simple-IVs(G, X, Y ) Let B be all nodes d-separated from Y in G Let D = De(An(X)) Construct a flow graph F (G) with nodes: {V + | V ∈ D} ∪ {V |V ∈ An(X)} ∪ {S, Y } and edges: {V + → W | V,W ∈ An(D) and V ← W ∈ E} ∪ {V + → V − | V ∈ An(X)} ∪ {V − → W | V,W ∈ An(X) and V → W ∈ E} ∪ {S → V + | V ∈ (D ∩M ∩B)} ∪ {X → Y | X ∈ X} Assign capacities to nodes in G: infinite capacity to S, Y ; zero capacity to nodes of Pa(Y ) \X and unit capacity to all other nodes. if an |X|-flow from S to Y in F (G) exists then return First nodes of the flow else return ⊥
منابع مشابه
On Searching for Generalized Instrumental Variables
Instrumental Variables are a popular way to identify the direct causal effect of a random variable X on a variable Y . Often no single instrumental variable exists, although it is still possible to find a set of generalized instrumental variables (GIVs) and identify the causal effect of all these variables at once. Till now it was not known how to find GIVs systematically or even test efficient...
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