Cluster allocation and intervention delivery

Specify assignment contamination and implementation

Randomize at the declared cluster level and retain stratification or restrictions. Contamination and fidelity concern intervention delivery; they do not justify reclassifying randomized assignment after observing outcomes.

Flow diagram

Cluster allocation and intervention deliveryF1.S1Define randomization unit andstrataF1.S2Allocate clusters with concealmentF1.S3Deliver assigned interventionsF1.S4Assess contamination and fidelityF1.S5Maintain cluster dispositionF1.N1Cluster delivery specificationElementUnitProcedureTimingResponsibilityRandomizationDeliveryFidelityContaminationWithdrawalF1.N2Assumptions and rationaleF1.N3Method and protocol evidenceF1.S0 Start flowCluster allocation and interventiondeliveryF1.S999 End flowEnd flow

Steps

Define randomization unit and strata

Record cluster definitions, restrictions and balancing variables.

Allocate clusters with concealment

Specify sequence generation, allocation ratio and implementation responsibilities.

Deliver assigned interventions

Document cluster-level and participant-level delivery mechanisms.

Assess contamination and fidelity

Track spillover, staff sharing and deviations between groups.

Maintain cluster disposition

Record withdrawal, mergers and changes to cluster membership.

Cluster allocation and intervention delivery

End flow

Tables and supporting information

Cluster delivery specification

Cluster delivery specificationElementUnitProcedureTimingResponsibilityRandomizationDeliveryFidelityContaminationWithdrawal

Allocation occurs at cluster level even when outcomes are measured in people.

Assumptions and rationale

Individual-level comparisons must account for cluster assignment and correlated outcomes.

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