Parameter: λ₁₂ Identified

Algebraic Equations:

σ₁₁λ₁₂-σ₁₂

Single Door Criterion:

{1} ⊥ {2,3,4} | {}

Parameter: λ₂₃ Identified

Algebraic Equations:

σ₂₂λ₂₃-σ₂₃,
σ₁₂λ₂₃-σ₁₃

Single Door Criterion:

{2} ⊥ {3} | {}
{2} ⊥ {3} | {1}

Instrumental Variable:

1 | {}

Parameter: λ₂₄ Identified

Algebraic Equations:

σ₂₃²λ₂₄-σ₂₂σ₃₃λ₂₄+σ₂₄σ₃₃-σ₂₃σ₃₄,
σ₁₃σ₂₃λ₂₄-σ₁₂σ₃₃λ₂₄+σ₁₄σ₃₃-σ₁₃σ₃₄,
σ₁₃²σ₂₄λ₂₄-σ₁₂σ₁₄σ₃₃λ₂₄+σ₁₄²σ₃₃-σ₁₃σ₁₄σ₃₄

Single Door Criterion:

{2} ⊥ {4} | {3}
{2} ⊥ {4} | {1,3}

Instrumental Variable:

1 | {3}

Parameter: λ₃₄ Identified

Algebraic Equations:

σ₂₃²λ₃₄-σ₂₃σ₂₄-σ₂₂σ₃₃λ₃₄+σ₂₂σ₃₄,
σ₁₃σ₂₃λ₃₄-σ₁₃σ₂₄-σ₁₂σ₃₃λ₃₄+σ₁₂σ₃₄,
σ₁₃²σ₂₄λ₃₄-σ₁₃σ₁₄σ₂₄-σ₁₂σ₁₄σ₃₃λ₃₄+σ₁₂σ₁₄σ₃₄

Single Door Criterion:

{3} ⊥ {1,4} | {2}
{3} ⊥ {4} | {1,2}

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₂₂ Identified

Algebraic Equations:

σ₁₂²-σ₁₁σ₂₂+σ₁₁ω₂₂

Parameter: ω₃₃ Identified

Algebraic Equations:

σ₂₃²-σ₂₂σ₃₃+σ₂₂ω₃₃,
σ₁₃σ₂₃-σ₁₂σ₃₃+σ₁₂ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

-σ₂₄²σ₃₃+2σ₂₃σ₂₄σ₃₄-σ₂₂σ₃₄²-σ₂₃²σ₄₄+σ₂₂σ₃₃σ₄₄+σ₂₃²ω₄₄-σ₂₂σ₃₃ω₄₄,
-σ₁₄σ₂₄σ₃₃+2σ₁₃σ₂₄σ₃₄-σ₁₂σ₃₄²-σ₁₃σ₂₃σ₄₄+σ₁₂σ₃₃σ₄₄+σ₁₃σ₂₃ω₄₄-σ₁₂σ₃₃ω₄₄,
-σ₁₄²σ₂₄σ₃₃+2σ₁₃σ₁₄σ₂₄σ₃₄-σ₁₂σ₁₄σ₃₄²-σ₁₃²σ₂₄σ₄₄+σ₁₂σ₁₄σ₃₃σ₄₄+σ₁₃²σ₂₄ω₄₄-σ₁₂σ₁₄σ₃₃ω₄₄

Total Effect of X₁ on X₃: λ₁₂λ₂₃ Identified

Each Parameter Identified

Back Door Criterion:


{1} ⊥ {2,3,4} | {}

Total Effect of X₁ on X₄: λ₁₂λ₂₃λ₃₄+λ₁₂λ₂₄ Identified

Each Parameter Identified

Back Door Criterion:


{1} ⊥ {2,3,4} | {}

Total Effect of X₂ on X₄: λ₂₃λ₃₄+λ₂₄ Identified

Each Parameter Identified

Back Door Criterion:


{2} ⊥ {3,4} | {}
{2} ⊥ {3,4} | {1}

Vanishing Ideal

Constraint Set:

σ₁₄σ₂₃-σ₁₃σ₂₄,
σ₁₄σ₂₂-σ₁₂σ₂₄,
σ₁₃σ₂₂-σ₁₂σ₂₃

All constraints are determinantal

Trek-separation:

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