Nonrandomized recruitment and assignment

Document enrollment and assignment mechanisms

Investigators assign the intervention, but without a random sequence. Document the selection mechanism and assignment timing. Historical controls additionally require attention to calendar changes and ascertainment differences.

Flow diagram

Nonrandomized recruitment and assignmentF1.S1Define recruitment and consentF1.S2State researcher assignment ruleF1.S3Assess baseline differencesF1.S4Track intervention receiptF1.S5Record comparison eligibilityF1.N1Assignment specificationElementRuleTimingDecision makerBias concernEligibilityAssignmentTreatmentreceiptComparisoneligibilityF1.N2Assumptions and rationaleF1.N3Method and protocol evidenceF1.S0 Start flowNonrandomized recruitment andassignmentF1.S999 End flowEnd flow

Steps

Define recruitment and consent

Specify eligibility, permissions and recruitment sources.

State researcher assignment rule

Record who assigns treatment, when and using which clinical or operational criteria.

Assess baseline differences

Document prognostic factors influencing assignment and outcome.

Track intervention receipt

Separate assignment, treatment initiation and deviations.

Record comparison eligibility

Assess overlap, contamination and selection limits.

Nonrandomized recruitment and assignment

End flow

Tables and supporting information

Assignment specification

Assignment specificationElementRuleTimingDecision makerBias concernEligibilityAssignmentTreatmentreceiptComparisoneligibility

This is researcher-assigned intervention, not naturally occurring exposure.

Assumptions and rationale

Without random allocation, baseline differences and unmeasured assignment factors can bias treatment comparisons.

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