Parameter: λ12 Identified

Algebraic Equations:

σ11λ1212

Single Door Criterion:

{1} ⊥ {2,3} | {}

Parameter: λ14 Identified

Algebraic Equations:

σ12σ13λ1411σ23λ1414σ2313σ24,
σ122λ1411σ22λ1414σ2212σ24

Single Door Criterion:

{1} ⊥ {3,4} | {2}
{1} ⊥ {4} | {2,3}

Parameter: λ23 Identified

Algebraic Equations:

σ22λ2323,
σ12λ2313

Single Door Criterion:

{2} ⊥ {3} | {}
{2} ⊥ {3,4} | {1}

Instrumental Variable:

1 | {}

Parameter: λ34 Identified

Algebraic Equations:

σ12σ13λ3412σ1411σ23λ3411σ24,
12σ14σ22122σ23λ3411σ22σ23λ3411σ22σ24

Instrumental Variable:

2 | {1}

Parameter: ω11 Identified

Algebraic Equations:

1111

Parameter: ω22 Identified

Algebraic Equations:

σ12211σ2211ω22

Parameter: ω33 Identified

Algebraic Equations:

σ23222σ3322ω33,
σ13σ2312σ3312ω33

Parameter: ω34 Identified

Algebraic Equations:

13σ14σ23132σ2412σ14σ3311σ24σ3312σ13σ3411σ23σ3412σ13ω3411σ23ω34,
12σ14σ23212σ13σ23σ2412σ14σ22σ3311σ22σ24σ33122σ23σ3411σ22σ23σ34122σ23ω3411σ22σ23ω34

Parameter: ω44 Identified

Algebraic Equations:

σ11σ142σ232-2σ11σ13σ14σ23σ2411σ132σ242122σ142σ33+2σ11σ12σ14σ24σ33112σ242σ33+2σ122σ13σ14σ34-2σ11σ12σ14σ23σ34-2σ11σ12σ13σ24σ34+2σ112σ23σ24σ34122σ132σ44+2σ11σ12σ13σ23σ44112σ232σ44122σ132ω44-2σ11σ12σ13σ23ω44112σ232ω44,
σ11σ142σ22σ232-2σ11σ12σ14σ232σ2411σ12σ13σ23σ242122σ142σ22σ33+2σ11σ12σ14σ22σ24σ33112σ22σ242σ33+2σ123σ14σ23σ34-2σ11σ12σ14σ22σ23σ34-2σ11σ122σ23σ24σ34+2σ112σ22σ23σ24σ34123σ13σ23σ44+2σ11σ122σ232σ44112σ22σ232σ44123σ13σ23ω44-2σ11σ122σ232ω44112σ22σ232ω44,
σ11σ142σ222σ232-2σ11σ12σ14σ22σ232σ2411σ122σ232σ242122σ142σ222σ33+2σ11σ12σ14σ222σ24σ33112σ222σ242σ33+2σ123σ14σ22σ23σ34-2σ11σ12σ14σ222σ23σ34-2σ11σ122σ22σ23σ24σ34+2σ112σ222σ23σ24σ34124σ232σ44+2σ11σ122σ22σ232σ44112σ222σ232σ44124σ232ω44-2σ11σ122σ22σ232ω44112σ222σ232ω44

Total Effect of X1 on X3: λ12λ23 Identified

Each Parameter Identified

Back Door Criterion:


{1} ⊥ {2,3,4} | {}

Total Effect of X1 on X4: λ12λ23λ3414 Identified

Each Parameter Identified

Back Door Criterion:


{1} ⊥ {2,3,4} | {}

Total Effect of X2 on X4: λ23λ34 Identified

Each Parameter Identified

Back Door Criterion:


{2} ⊥ {3,4} | {1}

Vanishing Ideal


Constraint Set:

σ13σ2212σ23

All constraints are determinantal

Trek-separation:

{1,2} ⊥ {2,3} | ({},{2})