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When to use staggered diff in diff treatment?
The ϕ j coefficients will then tell you how long it takes for your treatment to reach its full effect, or whether it persists/fades out after implementation. Another recent (working) paper which uses staggered diff-in-diff and that you can consult is Gipper et al (2016). Hope this helps!
When to use difference in differences ( DID ) method?
In this methodological section I will explain the issues with difference-in-differences (DiD) designs when there are multiple units and more than two time periods, and also the particular issues that arise when the treatment is conducted at staggered periods in time.
What do you call staggered difference in differences?
What you are attempting to do is sometimes referred to as staggered difference-in-differences. So you have units which receive a treatment at different points in time. Your specification,
How to do regression diff with different treatment timings?
So you have units which receive a treatment at different points in time. Your specification, would be one way of dealing with this, where y i t is the outcome for country i in year t, α i and δ t are country and year dummies, and D i k is an indicator which is equal to one for country i adopting the policy in all k ≥ t periods.
What’s the difference between Diff and diff in diff?
Thanks to its apparent simplicity, diff-in-diff can be mistaken for a “quick and easy” way to answer causal questions. However, as we peer under the hood of diff-in-diff and illuminate its inner workings, we see that the reality is more complex. The table below provides a guide to the notation we use throughout this site.
Why do we use control group in DIFF-in-diff?
In diff-in-diff, we use data from the control group to impute untreated outcomes in the treated group. This is the “secret sauce” of diff-in-diff. Using the control group helps us learn something about the unobservable counterfactual outcomes of the treated group.