Staggered DID Model The treatment and control groups in staggered DID model: The treatment periods for a,b,and c are t,t2,and t3 ·t3>t2> A control d without any treatment. Yit a BTreatit +8i+8t Eit If we estimate staggered DID model,what are the treatment and control groups? What is the economic implication for the coefficient B? 11
• The treatment and control groups in staggered DID model: • The treatment periods for a, b, and c are t1 , t2 , and t3 . • t3 > t2 > t1 . • A control d without any treatment. 𝑌𝑖,𝑡 = 𝛼 + 𝛽1𝑇𝑟𝑒𝑎𝑡𝑖,𝑡 + 𝛿𝑖 + 𝛿𝑡 + 𝜀𝑖,𝑡 • If we estimate staggered DID model, what are the treatment and control groups? • What is the economic implication for the coefficient 𝛽1? 11 Staggered DID Model
Staggered DID Model ·Discuss: Whether the estimation is biased? Staggered timing of treatment;Static treatment effects. The matched treatment and control groups for a,b,and c in different period. The treatment effect revealed by the difference between the potential outcomes. 12
• Discuss: • Whether the estimation is biased? • Staggered timing of treatment; Static treatment effects. • The matched treatment and control groups for a, b, and c in different period. • The treatment effect revealed by the difference between the potential outcomes. 12 Staggered DID Model
Staggered DID Model The characteristic for staggered treatment: Staggered timing of treatment;Static treatment effects but differ across treatment groups. Staggered timing of treatment;Dynamic treatment effects. Staggered timing of treatment;Dynamic treatment effects but differ across treatment groups. What will happen if we still use staggered DID model? Y.t=a+B1 Treatit+di+δ：+ei.t 13
• The characteristic for staggered treatment: • Staggered timing of treatment; Static treatment effects but differ across treatment groups. • Staggered timing of treatment; Dynamic treatment effects. • Staggered timing of treatment; Dynamic treatment effects but differ across treatment groups. • What will happen if we still use staggered DID model? 𝑌𝑖,𝑡 = 𝛼 + 𝛽1𝑇𝑟𝑒𝑎𝑡𝑖,𝑡 + 𝛿𝑖 + 𝛿𝑡 + 𝜀𝑖,𝑡 13 Staggered DID Model