This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demography and family planning, Subject name: Social & Preventive Medicine
Failure rate of contraceptive method is determined by 
Select and explain. 
A. Pearl index, B. Half life, C. Number of accidental pregnancies, D. Period of contraceptive practice continued
A: Pearl index
Answer: A: Pearl index 
Explanation: Two methods have been used to measure contraceptive efficacy: 1. Pearl index and 2. Life table analysis Pearl index is defined as the number of failure rates per 100 woman years of exposure Reference : Park&;s textbook of preventive and social medicine, 23rd edition, Page no: 510