RMP.7:4.2 - Recover distinct contributions before counting support
Distinguish a report from its underlying studies and material, a source author’s interpretation from the material it interprets, and either from the proposed synthesis finding.
| Source relation | Consequence for synthesis |
|---|---|
| Several reports concern one study | Combine their useful information into the study’s contribution; resolve discrepancies and retain supplementary detail. Repeated reports do not supply independent study estimates. |
| One report contains several studies | Recover the actual studies and their relation; the document count does not determine the number of independent contributions. |
| Samples, controls, records or data overlap | Preserve the overlap and use an analysis that accounts for it, or a justified selection or grouping. A different title or author list does not establish independence. |
| Later accounts copy or interpret one earlier source | Recover the common source and the distinct interpretations. Copying is evidence of transmission; independent corroboration needs an independent evidential contribution. |
| A source adds context or a different outcome | Retain that contribution for the question it can answer. Its usefulness does not make it another estimate of the same quantity. |
Keep contrary findings and disagreements between reports visible. If dependence cannot be recovered well enough for the intended combination, qualify or withhold that combination and state what comparison remains possible.