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Causal structure for follow-up of a clinic-based cohort that includes tracking of a sample of patients lost to follow-up. Here, loss to follow-up leads to final outcome ascertainment both through tracking (among patients who are lost) and through passive outcome ascertainment by initial loss to follow-up (i.e., outcome ascertainment through observation at the clinic alone). In this causal diagram, after reweighting, there are no undirected pathways from sex to vital status.
