Causality, Causal Inference, Backdoor, Frontdoor, Instrumental Variable.
stats::lm(y~stage1_predict, data = df) summary(stage2_fit) In our example, the instrumental variable method estimates the causal effect of X on Y to be b_iv = 0.96, very close to the BD adjustment methods. 6. Front-door adjustment (Observing X, Y and FD) Even if we can measure neither IV nor BD, it