Time-series data preparation

Align intervals outcomes and denominators

Keep observation intervals, population denominators and definitions consistent. Investigate missing periods and recording-system changes; they can mimic an intervention effect.

Flow diagram

Time-series data preparationF1.S1Define repeated outcome measuresF1.S2Align intervals and interventiondatesF1.S3Assess definition stabilityF1.S4Handle missing intervalsF1.S5Freeze analysis-ready seriesF1.N1Series data dictionarySeriesOutcomeIntervalDenominatorCoverageDefinitionchangesInterventionseriesComparisonseriesCalendarcovariatesF1.N2Assumptions and rationaleF1.N3Method and protocol evidenceF1.S0 Start flowTime-series data preparationF1.S999 End flowEnd flow

Steps

Define repeated outcome measures

Record numerator, denominator and population coverage.

Align intervals and intervention dates

Use consistent intervals and preserve partial exposure periods.

Assess definition stability

Document coding, reporting delays and changing population composition.

Handle missing intervals

Specify missingness, imputation and sensitivity without silent interpolation.

Freeze analysis-ready series

Version transformations, denominators and control-series alignment.

Time-series data preparation

End flow

Tables and supporting information

Series data dictionary

Series data dictionarySeriesOutcomeIntervalDenominatorCoverageDefinitionchangesInterventionseriesComparisonseriesCalendarcovariates

Control rows are optional; keep repeated time intervals and units explicit.

Assumptions and rationale

Aggregated rates require their denominators; changing definitions can mimic intervention effects.

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