Parameter: λ12 Identified

Algebraic Equations:

σ11λ1212

Single Door Criterion:

{1} ⊥ {2,3,4} | {}
{1} ⊥ {2,4} | {3}

Parameter: λ24 Identified

Algebraic Equations:

σ12λ2414

Instrumental Variable:

1 | {}
1 | {3}

Parameter: λ34 Identified

Algebraic Equations:

σ14σ2212σ23λ3412σ24

Instrumental Variable:

1 | {2}

Parameter: ω11 Identified

Algebraic Equations:

1111

Parameter: ω22 Identified

Algebraic Equations:

σ12211σ2211ω22

Parameter: ω23 Identified

Algebraic Equations:

2323

Parameter: ω33 Identified

Algebraic Equations:

3333

Parameter: ω34 Identified

Algebraic Equations:

σ14σ23214σ22σ3312σ24σ3312σ23σ3412σ23ω34

Parameter: ω44 Identified

Algebraic Equations:

σ142σ22σ232142σ222σ33+2σ12σ14σ22σ24σ33122σ242σ33-2σ12σ14σ22σ23σ34+2σ122σ23σ24σ34122σ232σ44122σ232ω44

Total Effect of X1 on X4: λ12λ24 Identified

Each Parameter Identified

Back Door Criterion:


{1} ⊥ {2,3,4} | {}
{1} ⊥ {2,4} | {3}

Vanishing Ideal


Constraint Set:

σ13

All constraints are determinantal

Trek-separation:

{1} ⊥ {3} | ({},{})