Multi-arm study contribution plan
=================================

StatMedAnalysis | Original downloadable worksheet | 6 November 2026

Prevent shared comparison groups from being counted repeatedly in a synthesis.

How to use this worksheet
Draw all eligible arms and the review comparisons they can inform. Identify which
participant groups would be reused if each contrast were entered independently. Choose a
justified combination, split or correlated-analysis strategy compatible with the
estimand. Preserve the original arm-level counts and assumptions.

Save a working copy and keep the original blank version. Use public, hypothetical or
aggregate information only; do not enter patient identifiers, credentials or confidential
records. Keep source evidence in your approved project workspace. Mark unresolved text
fields UNKNOWN or NOT REPORTED with a reason; never substitute zero for an unknown count.

Project/version __________________  Prepared by role/date __________________

Working fields
1. Study arms and sample sizes
Response/evidence: _________________________________________________________
___________________________________________________________________________

2. Eligible review comparisons
Response/evidence: _________________________________________________________
___________________________________________________________________________

3. Shared participants or controls
Response/evidence: _________________________________________________________
___________________________________________________________________________

4. Outcome and effect scale
Response/evidence: _________________________________________________________
___________________________________________________________________________

5. Selected handling strategy
Response/evidence: _________________________________________________________
___________________________________________________________________________

6. Calculation and weighting consequences
Response/evidence: _________________________________________________________
___________________________________________________________________________

7. Correlation assumptions if required
Response/evidence: _________________________________________________________
___________________________________________________________________________

8. Sensitivity analysis and reporting note
Response/evidence: _________________________________________________________
___________________________________________________________________________

Hypothetical worked case
A fictional three-arm trial compares low dose and high dose with one control group.
Entering both contrasts with the full control group as independent studies overstates
the information in that control group.

Decision rule and limitations
Approve contributions only after participant reuse is explicitly handled by an
appropriate method. Splitting a control count is an approximation whose implementation
depends on the outcome and analysis.

Decision _______________________  Remaining uncertainty ____________________
Next action ____________________  Owner / review date ______________________
Independent check and discrepancy resolution _______________________________

Official method or reporting reference checked 6 November 2026
https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-10

This is an original planning aid, not an official checklist, validated instrument,
clinical recommendation or certificate of expert approval. Apply the referenced
guidance to the specific design and record any additional requirements.