Why 27% more is not 27 extra percentage points

Invented starting proportions explain the arithmetic only; they are not observed trial rates or a calculator for an individual.

Illustrative starting rateRate multiplied by 1.27
10%10% → 12.7%: +2.7 points
20%20% → 25.4%: +5.4 points

[1]

What was actually compared

The 2023 Cochrane public summary and abstract describe a patch plus a faster-acting NRT form compared with a single NRT form. The long-term cessation comparison contains 16 studies and 12,169 participants, not all 43,327 people in the wider review. Follow-up was at least six months; participants were mostly adults motivated to quit. Other components of support had to be matched between groups.

[1]

How to read the estimate

For this comparison, the abstract reports a risk ratio of 1.27 (95% confidence interval 1.17–1.37), with high-certainty evidence for the cessation outcome. That is a relative comparison of trial groups, not a 27-percentage-point increase and not an individual chance of quitting. Without a baseline quit proportion and comparable setting it gives no single absolute benefit.

[1]

Same result, different absolute differences

Illustrative arithmetic, not trial data or a prediction: if 10% of one group reached an outcome, multiplying by a risk ratio of 1.27 gives 12.7%, a difference of 2.7 percentage points. With a 20% starting proportion, the same multiplication gives 25.4%, a 5.4-point difference. The relative ratio stays the same while the absolute difference changes. Neither starting proportion is supplied here as your expected quit rate.

[1]

Why that finding does not settle a regimen

High certainty for the cessation outcome does not settle questions that other outcomes or study comparisons answer less fully. Nor does it determine strength, duration, sequence or personal suitability. A group result does not turn any two products into interchangeable alternatives, or transfer the same strategy automatically to pregnancy or another clinical setting.

[1]

Check which evidence version you are reading

The review was published in June 2023 and searched to April 2022. Its public abstract, not a full-review reanalysis, is the basis for the figures here. The combination comparison is not a test of every product pair. A qualified local clinician or pharmacist is the appropriate source for actual product instructions; this evidence explanation supplies none.

[1]

Sources

The central claims on this page were checked against the sources below.

  1. Cochrane: Combination NRT: 2023 review, public summary and statistical abstract (search to April 2022)

    Sources checked: 2026-10-11

General medicine education. Ask a qualified clinician or pharmacist about the actual product and your circumstances; this page cannot choose treatment or change its instructions.