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. Author manuscript; available in PMC: 2018 Nov 30.
Published in final edited form as: Stat Med. 2017 Aug 8;36(27):4243–4265. doi: 10.1002/sim.7430

Table 2.

Consequence of the sequential ignorability and no interaction assumptions on parameters within the CA framework.

Assumption

1. α2 = α3 = 0 2. β3 = β5 = 0
No unmeasured confounders for S No unmeasured confounders for T
ρs 0
α2(α2+α3)(α22+δS02)((α2+α3)2+δS12)
ρ00
β2δS02δS02(β32+β22δS02+δT02)
β2(α22+δS02)(α22+δS02)((β2α2)2+β22δS02+δT02)
ρ01 0
α2(β2+β4)(α2+α3)(α22+δS02)([(β2+β4)(α2+α3)]2+(β2+β4)2δS12+δT12)
ρ10 0
(α2+α3)β2α2((α2+α3)2+δS12)((β2α2)2+β22δS02+δT02)
ρ11
(β2+β4)δS12δS12((β3+β5)2+(β2+β4)2δS12+δT12)
(β2+β4)((α2+α3)2+δS12)((α2+α3)2+δS12)([(β2+β4)(α2+α3)]2+(β2+β4)2δS12+δT12)
ρt
β3(β3+β5)(β32+β22δS02+δT02)((β3+β5)2+(β2+β4)2δS12+δT12)
β2α2(β2+β4)(α2+α3)((β2α2)2+β22δS02+δT02)([(β2+β4)(α2+α3)]2+(β2+β4)2δS12+δT12)
γ0
(β1+β4(α0+α1))-α1β4(δS12δS02+δS12)
(β1+β4(α0+α1))-α1β4(α32+α3α2+δS12α32+δS02+δS12)
γ1
β2+β4(δS12δS02+δS12)
β2+β4(α32+α3α2+δS12α32+δS02+δS12)

Assumption
3. β4 = α2 = α3 = 0 4. β4 = β3 = β5 = 0
No interaction, no unmeasured confounders for S No interaction, no unmeasured confounders for T

ρs 0
α2(α2+α3)(α22+δS02)((α2+α3)2+δS12)
ρ00
β2δS02δS02(β32+β22δS02+δT02)
β2(α22+δS02)(α22+δS02)((β2α2)2+β22δS02+δT02)
ρ01 0
α2β2(α2+α3)(α22+δS02)([β2(α2+α3)]2+β22δS12+δT12)
ρ10 0
(α2+α3)β2α2((α2+α3)2+δS12)((β2α2)2+β22δS02+δT02)
ρ11
β2δS12δS12((β3+β5)2+β22δS12+δT12)
β2((α2+α3)2+δS12)((α2+α3)2+δS12)([β2(α2+α3)]2+β22δS12+δT12)
ρt
β3(β3+β5)(β32+β22δS02+δT02)((β3+β5)2+β22δS12+δT12)
α2β22(α2+α3)((β2α2)2+β22δS02+δT02)([β2(α2+α3)]2+β22δS12+δT12)
γ0 β1 β1
γ1 β2 β2