Causal Inference, Instrumental Variables, Stats 361, Stanford, Data Science.
running OLS of Y_i on W_i” (Wager, 2020, p68) (conversely, we cannot do it without unconfoundedness assumption). Imagine a scenario where the x-axis (treatments) of Figure 1 having more values like 0,1,2,3,4,... and some dots over each of them like Figure 2. The results shown in Figure 2 show that