Multiply the assumed baseline risk by the relative effect to derive the absolute effect, then record the baseline and its source in the SoF row so readers can reproduce the arithmetic.
A Summary of Findings (SoF) table pairs a relative effect with an assumed baseline risk to show readers what the effect means in absolute terms. Cochrane guidance on interpreting results treats absolute and relative effects as complementary presentations, and GRADE SoF guidance supplies the table structure that holds the baseline, the relative effect, and the resulting absolute difference.
Worked example
Suppose a winter-health review reports a relative risk of 0.80 for an outcome, and you assume a baseline risk of 200 events per 1,000 people in the population you are addressing.
- Convert the baseline to a proportion: 200 per 1,000 = 0.20.
- Multiply by the relative effect: 0.20 × 0.80 = 0.16, or 160 events per 1,000.
- Subtract to get the absolute difference: 200 − 160 = 40 fewer events per 1,000 people.
Record the row as: assumed baseline risk 200 per 1,000; relative effect RR 0.80; corresponding absolute effect 40 fewer per 1,000.
Choosing and documenting the baseline
State where the baseline came from, such as the control-group risk in the included studies or a risk from the population you are addressing. Cochrane interpretation guidance frames applicability around whether the populations, settings, and outcomes in the evidence match the decision context, so the baseline should reflect the population the SoF row is meant to inform. Add a short note naming the baseline source and, when relevant, why that population was chosen.
Handling uncertainty
Apply the same multiplication to the confidence limits of the relative effect to show the range of absolute effects. Report the interval alongside the point estimate so readers see how much the absolute difference could vary at the stated baseline.