Comparative change diagnostics and sensitivity

Assess trends anticipation and spillovers

Pre-intervention patterns help assess plausibility but cannot verify unobserved post-intervention parallel trends. Investigate anticipation, composition, alternative controls and sensitivity to plausible departures.

Flow diagram

Comparative change diagnostics and sensitivityF1.S1Assess pre-intervention patternsF1.S2Assess anticipation and spilloversF1.S3Examine composition and commonshocksF1.S4Plan alternative comparisonsF1.S5Bound interpretationF1.N1Comparative change sensitivityConcernAssessmentAlternativeInterpretationPretrendsAnticipationSpilloversCompositionControl choiceF1.N2Assumptions and rationaleF1.N3Method and protocol evidenceF1.S0 Start flowComparative change diagnostics andsensitivityF1.S999 End flowEnd flow

Steps

Assess pre-intervention patterns

Specify graphical and statistical assessments with their power limitations.

Assess anticipation and spillovers

Evaluate alternative exposure windows and contamination routes.

Examine composition and common shocks

Document differential missingness, migration and contemporaneous changes.

Plan alternative comparisons

Vary control cohorts, periods and justified trend assumptions.

Bound interpretation

Report uncertainty and sensitivity to identification assumptions.

Comparative change diagnostics and sensitivity

End flow

Tables and supporting information

Comparative change sensitivity

Comparative change sensitivityConcernAssessmentAlternativeInterpretationPretrendsAnticipationSpilloversCompositionControl choice

Prespecify checks; do not treat a passed test as proof.

Assumptions and rationale

Failure to reject pretrend differences does not establish parallel counterfactual trends.

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