Factorial recruitment and combination allocation

Assign participants across factor combinations

Specify eligible combinations and the randomization of each factor. Restrictions, differing eligibility or nonindependent assignments can change which contrasts are estimable.

Flow diagram

Factorial recruitment and combination allocationF1.S1Define eligible factor combinationsF1.S2Recruit and obtain consentF1.S3Randomize to combinationsF1.S4Track receipt by factorF1.S5Reconcile combination dispositionF1.N1Factor allocation matrixCombinationFactor A levelFactor B levelAllocationEligibilityCombination ACombination BCombination CCombination DF1.N2Assumptions and rationaleF1.N3Method and protocol evidenceF1.S0 Start flowFactorial recruitment and combinationallocationF1.S999 End flowEnd flow

Steps

Define eligible factor combinations

Specify factors, levels and any incompatible combinations.

Recruit and obtain consent

Assess eligibility for each factor and shared study participation.

Randomize to combinations

Prespecify allocation, concealment, stratification and randomization unit.

Track receipt by factor

Record actual treatments, adherence and crossovers separately for each factor.

Reconcile combination disposition

Preserve arm membership without double-counting pooled main-effect groups.

Factorial recruitment and combination allocation

End flow

Tables and supporting information

Factor allocation matrix

Factor allocation matrixCombinationFactor A levelFactor B levelAllocationEligibilityCombination ACombination BCombination CCombination D

Editable two-factor starting matrix; add/remove combinations to match the design.

Assumptions and rationale

Factors and combinations differ from unrelated parallel arms. Avoid treating pooled and combination counts as one disjoint partition.

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