Sources and data preparation

Establish suitable analysis-ready data

A large dataset can still omit the clinical variables or follow-up needed for the question. Review source coverage, linkage and changes in coding before finalizing eligibility and analysis. A recorded absence may mean no capture rather than no disease.

Flow diagram

Sources and data preparationF1.S1Permissions and source accessF1.S2Assess source suitabilityF1.S3Link and deduplicate recordsF1.S4Check and resolve data qualityF1.S5Derive analysis-ready dataF1.S6Review and freeze data versionF1.N1Source suitabilitySourcePopulationcoverageDatesKey variablesLimitationsPermissionF1.N2Derivation and quality logVariableSourceDefinitionTransformationCheckVersionF1.N3Data evidenceF1.S0 Start flowSources and data preparationF1.S999 End flowEnd flow

Steps

Permissions and source access

Document legal basis, data agreements, governance and versioned extracts.

Assess source suitability

Assess coverage, clinical detail, missingness and fitness for each study question.

Link and deduplicate records

Specify linkage keys, linkage error assessment and participant versus episode identifiers.

Check and resolve data quality

Review validity, coding changes, duplicates and temporal consistency.

Derive analysis-ready data

Version code lists and derivations, retaining provenance and transformations.

Review and freeze data version

Record outstanding limitations and reproducible extract/version identifiers.

Sources and data preparation

End flow

Tables and supporting information

Source suitability

Source suitabilitySourcePopulationcoverageDatesKey variablesLimitationsPermission

Establish source fitness before analysis.

Derivation and quality log

Derivation and quality logVariableSourceDefinitionTransformationCheckVersion

Keep source-to-analysis lineage.

Data evidence

Attach source validation reports, coding definitions or coverage documentation.

Sources