Designing Difference in Difference Studies With Staggered Treatment Adoption: Key Concepts and Practical Guidelines

Seth Freedman, Alex Hollingsworth (), Kosali Simon, Coady Wing and Madeline Yozwiak

No 31842, NBER Working Papers from National Bureau of Economic Research, Inc

Abstract: Difference-in-Difference (DID) estimators are a valuable method for identifying causal effects in the public health researcher’s toolkit. A growing methods literature points out potential problems with DID estimators when treatment is staggered in adoption and varies with time. Despite this, no practical guide exists for addressing these new critiques in public health research. We illustrate these new DID concepts with step-by-step examples, code, and a checklist. We draw insights by comparing the simple 2 × 2 DID design (single treatment group, single control group, two time periods) with more complex cases: additional treated groups, additional time periods of treatment, and with treatment effects possibly varying over time. We outline newly uncovered threats to causal interpretation of DID estimates and the solutions the literature has proposed, relying on a decomposition that shows how the more complex DID are an average of simpler 2X2 DID sub-experiments.

JEL-codes: I0 I1 (search for similar items in EconPapers)
Date: 2023-11
New Economics Papers: this item is included in nep-ecm, nep-exp and nep-hea
Note: AG EH
References: Add references at CitEc
Citations: View citations in EconPapers (4)

Downloads: (external link)
http://www.nber.org/papers/w31842.pdf (application/pdf)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nbr:nberwo:31842

Ordering information: This working paper can be ordered from
http://www.nber.org/papers/w31842

Access Statistics for this paper

More papers in NBER Working Papers from National Bureau of Economic Research, Inc National Bureau of Economic Research, 1050 Massachusetts Avenue Cambridge, MA 02138, U.S.A.. Contact information at EDIRC.
Bibliographic data for series maintained by ().