Pertaining to the failure rate of contraceptives when adherence to prescribed instruction is unknown, theoretical effectiveness.
When a treatment fails to achieve its intended results, the failure may be due to the method employed or its use. For example, a contraceptive failure may occur because the method was inadequate or because it really was not employed or was employed improperly. Thus the “method effectiveness” or the “use effectiveness” may have been at fault, and the failure may have been a “method failure” or a “use failure.”