Although the reproductive calendar is the primary tool for measuring contraceptive dynamics in low-income settings, the reliability of calendar data has seldom been evaluated, primarily due to the lack of longitudinal panel data. In this research, we evaluated the reproductive calendar using PMA data. We used population-based longitudinal data from nine settings in seven countries: Burkina Faso, Nigeria (Kano and Lagos States), the Democratic Republic of Congo (Kinshasa and Kongo Central Provinces), Kenya, Uganda, Cote d’Ivoire, and India.
Overall, we find that the reliability of the calendar is in the “moderate/substantial” range for nearly all geographies and tests. Measures of the complexity of the calendar are associated with reliability. We also find that women who were using contraception without their partners/husband’s knowledge (i.e., covertly) were less likely to report reliably in several countries.