Hi, I am trying to use SAS to fit an instrumental variable analysis on a binary outcome. From what I could find online, this can be done using the 2SLS estimator in proc syslin? The data are as follows: death (outcome, yes/no), gene (exposure, class variable), which regulates "normalized" (mediator, continuous variable). The value of "normalized" is also affected by cohort, female, trg_i, and crp_log. What I want to know is: 1. If "normalized" (as an instrumental variable) is a causal risk factor for death. 2. If there is evidence for bias when using "normalized" as an observational variable vs. as an instrumental variable (using the Durbin-Wu-Hausman test) on risk of death. Here is my code: proc syslin data=causalmed 2sls; endogenous normalized; instruments gene cohort female trg_i crp_log; model normalized = gene cohort female trg_i crp_log; model death = normalized cohort female trg_i crp_log; run; proc model data=causalmed; endogenous normalized; instruments gene; death = pnormalized*normalized + interc; fit death / ols 2sls hausman; quit; Is my code correct? Any help would be much appreciated. Thanks!
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