Comparative change groups and adoption timing

Define units treatment and periods

Define who adopts the intervention, when adoption occurs and which units are eligible comparisons. Investigate anticipation, spillovers and differential external shocks before estimation.

Flow diagram

Comparative change groups and adoption timingF1.S1Define units and interventionF1.S2Record adoption cohortsF1.S3Define comparison eligibilityF1.S4Define periods and targetpopulationF1.S5Assess interference and supportF1.N1Adoption and comparison registerCohortAdoption ruleEligiblecontrolsPeriodsSpilloverconcernTreatmentcohortNever treatedNot yet treatedF1.N2Assumptions and rationaleF1.N3Method and protocol evidenceF1.S0 Start flowComparative change groups andadoption timingF1.S999 End flowEnd flow

Steps

Define units and intervention

Specify treatment at individual, organization or geographical level.

Record adoption cohorts

Identify when treatment starts and whether reversals or anticipation occur.

Define comparison eligibility

Select never-treated or not-yet-treated units as justified by the estimator.

Define periods and target population

Specify baseline, follow-up, entry and composition changes.

Assess interference and support

Record spillovers, shared shocks and comparable covariate support.

Comparative change groups and adoption timing

End flow

Tables and supporting information

Adoption and comparison register

Adoption and comparison registerCohortAdoption ruleEligiblecontrolsPeriodsSpilloverconcernTreatmentcohortNever treatedNot yet treated

Do not automatically use already-treated units as controls.

Assumptions and rationale

Comparison eligibility depends on adoption timing, anticipation and the estimand.

Method and protocol evidence

Attach the protocol, methodological sources and versioned software specification supporting these decisions. Record citations and provenance; do not enter participant identifiers.

Sources