Contraception effectiveness percentages reflect typical per-year use rather than per-event use

the verdict

SUPPORTED

the evidence backs this

Recorded sources

3 sources for · 0 against

Counts group repeated records of the same source within each side. They do not measure evidence strength or source independence.

Contraception effectiveness and failure percentages are standardly reported as typical-use or perfect-use rates over a one-year period (such as per 100 woman-years) rather than as a probability per individual sexual act.

The analysis

The provided literature consistently measures contraceptive efficacy and failure using metrics like the Pearl Index (pregnancies per 100 woman-years) and multi-month or annual life-table failure rates (such as 12-month or 13-cycle rates), which supports the claim that contraception effectiveness percentages reflect typical per-year use rather than per-event use.

Evidence for · 3

Typical-use contraceptive failure rates in 43 countries with Demographic and Health Survey data: summary of a detailed report

Recorded source metadata

C. Polis, S. Bradley, A. Bankole, Tsuyoshi Onda, T. Croft, Susheela Singh. Typical-use contraceptive failure rates in 43 countries with Demographic and Health Survey data: summary of a detailed report. 2016. https://doi.org/10.1016/j.contraception.2016.03.011

The study estimates typical-use contraceptive failure rates across 12, 24, and 36 months of use, reflecting per-year risk rather than per-event risk.

Source citation format

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More for · 2

Perfect-use and typical-use Pearl Index of a contraceptive mobile app

Recorded source metadata

E. B. Scherwitzl, O. Lundberg, H. Kallner, H. Kallner, K. Danielsson, James Trussell, James Trussell, R. Scherwitzl. Perfect-use and typical-use Pearl Index of a contraceptive mobile app. 2017. https://doi.org/10.1016/j.contraception.2017.08.014

The study evaluates the typical-use Pearl Index as the number of pregnancies per 100 woman-years, tracking failure over annual periods of use.

Source citation format

Perfect- and typical-use effectiveness of the Dot fertility app over 13 cycles: results from a prospective contraceptive effectiveness trial

Recorded source metadata

V. Jennings, Liya T Haile, R. Simmons, J. Spieler, Dominick C Shattuck. Perfect- and typical-use effectiveness of the Dot fertility app over 13 cycles: results from a prospective contraceptive effectiveness trial. 2019. https://doi.org/10.1080/13625187.2019.1581164

The study determines typical-use failure rates using multi-censoring life-table analysis over 13 cycles, which corresponds to per-year use effectiveness.

Source citation format

The paper trail · every fact has a biography

first checked02 Aug 2026

judged → SUPPORTED · 8802 Aug 2026

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