actual failure rate

Definition

The average effectiveness or failure rate for a contraceptive or contraceptive method including failure of the device or method and failure due to improper use or non-use. The theoretical failure rate for condoms is +/- 5% whereas its actual failure rate is +/- 15%. The theoretical failure rate of an oral contraceptive may be 0.5% but its actual failure rate will be much higher because of manufacturing defects in the pill itself or because the woman failed to take it every day.

Synonym: actual effectiveness rate.
See also: theoretical effectiveness or failure rate.