Reading an absolute reduction and a relative measure
Two descriptions of a difference can sound very different and still be compatible.
A hypothetical example, not attributed to a medicine.
Two descriptions of a difference can sound very different and still be compatible.
The example
Imagine two hypothetical groups with risks of the same event of 10% and 8% over the same period. The absolute difference is 2 percentage points. The relative risk reduction is 20%: (10 − 8) ÷ 10. These describe the same example; they are not findings from a real trial.
What the example does not calculate
A hazard ratio incorporates timing information and is not obtained simply by dividing these percentages. CONSORT calls for appropriate absolute and relative measures for binary outcomes. Before interpreting a percentage, ask which measure it is, what it compares and which period it covers.
Professional context / Contexto profesional
The example describes hypothetical cumulative risks, not person-time rates or a survival analysis. It calculates neither an individual benefit nor a time-adjusted NNT.
Evidence / Evidencia
Our own illustrative arithmetic and a trial-reporting guideline.
Limitations / Limitaciones
No fabricated patient or study data are presented.