Lecture: Difference-in-Difference (DID)

5 DID Based on Observed Data Let DA be the after-treatment dummy (or time dummy), and DT be the treatment dummy. The dependent variable y measures the outcome. Consider the pooled regression that includes DA; DT and their interaction term y = b0 + b1DA + b2DT + b3(DADT)+ b4x + u (1) 1. b0 measures the average before outcome for control group 2. b1 measures (average after outcome - average ... ................
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