Fertility measurement in data-constrained settings: possibilities and limitations of a Facebook-recruited network reporting survey in Senegal

Reliable fertility statistics are crucial for monitoring population dynamics, yet traditional data sources are often limited in low- and middle-income countries. This study evaluates a Facebook-recruited survey combined with network reporting to estimate fertility in Senegal. Respondents reported on members of their social networks to address undercoverage from limited internet access. Both respondent and network samples overrepresent younger and more educated individuals, while rural populations and those with lower education are underrepresented. Network reporting partially mitigates these gaps by including non-Facebook users. However, respondents and their network members remain similar to one another in terms of gender, age, and education. Total fertility rates (TFR) are approximated reasonably well, but age-specific fertility rates (ASFR) are less accurate: fertility is underestimated at ages 15–24 and overestimated at 35–49. Urban network estimates align better with DHS benchmarks than rural estimates. Thus, future development of this approach holds most promise in urban areas, where estimates could be improved through experimental testing of different network definitions, advertisement designs, and weighting adjustments to provide timely, low-cost directional fertility information.