Parameter: λ14

Parameter: λ23 Identified

Algebraic Equations:

σ22λ2323

Single Door Criterion:

{2} ⊥ {1,3,4} | {}
{2} ⊥ {3,4} | {1}

Parameter: λ34 Identified

Algebraic Equations:

σ33λ3434,
σ23λ3424

Single Door Criterion:

{3} ⊥ {1,4} | {}
{3} ⊥ {1,4} | {2}
{3} ⊥ {4} | {1}
{3} ⊥ {4} | {1,2}

Instrumental Variable:

2 | {}
2 | {1}

Parameter: ω11 Identified

Algebraic Equations:

1111

Parameter: ω14

Parameter: ω22 Identified

Algebraic Equations:

2222

Parameter: ω33 Identified

Algebraic Equations:

σ23222σ3322ω33

Parameter: ω44

Total Effect of X2 on X4: λ23λ34 Identified

Each Parameter Identified

Back Door Criterion:


{2} ⊥ {1,3,4} | {}
{2} ⊥ {3,4} | {1}

Vanishing Ideal


Constraint Set:

σ13,
σ12,
σ24σ3323σ34

All constraints are determinantal

Trek-separation:

{1} ⊥ {2,3} | ({},{})
{2,1} ⊥ {2,3} | ({2},{})
{4,1} ⊥ {2,3} | ({4},{})
{1,2} ⊥ {2,3} | ({},{2})
{2,3} ⊥ {3,1,4} | ({},{3})
{1,2,3} ⊥ {3,1,4} | ({1},{3})
{4,2,3} ⊥ {3,1,4} | ({4},{3})