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Fig. 1 | BMC Medical Research Methodology

Fig. 1

From: A comparison of methods to estimate the survivor average causal effect in the presence of missing data: a simulation study

Fig. 1

Causal diagram for the effect of iron intake on age-related macular degeneration. V represents the vector of participant demographics (e.g. age and sex) recorded at baseline. Exposure, A, is also recorded at baseline. Z is an indicator of survival until the start of the follow-up wave. R is an indicator of attendance at the follow-up study wave when outcome (Y, age-related macular degeneration) was ascertained. An indicator genotype, U, is unmeasured, as is D, an indicator for area of residence. a A scenario where missing outcome data are missing at random. b Conditioning on Z (a collider between the exposure and U) will unblock the backdoor pathway (dashed line) from the exposure to the outcome through U

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