Contraceptive efficacy is measured by
Contraceptive Efficacy: Is assessed by measuring the number of unplanned pregnancies that occur during a specified period of exposure and use of a contraceptive method. Two methods used are:

Pearl Index
Life table analysis

Life Table Analysis (LTA) as measure of contraceptive efficacy:
– LTA calculates a failure rate per month of use
– Better measure than PI
Pearl Index and Life table analysis
Pearl Index only
Life table analysis and Couple protection rate
Pearl Index and Couple protection rate