Estimating impacts of Nigeria’s 2012 floods: Views from the ground and views from the sky

Floods are one of the most damaging natural hazards globally, but measuring local impacts is complicated by challenges in the measurement of flood incidence, especially in Global South contexts. This paper examines household-level impacts of the major 2012 floods in Nigeria and studies how estimated impacts depend on approaches to flood measurement. We construct seven different measures of flood incidence using survey reports and flood databases using both administrative and media reports as well as satellite imagery. We find limited cross-measure correlations in flood incidence, and exposure estimates range from 0% to 13% of the total country population and 2% to 38% of survey households. The measures also disagree on whether household flood exposure is associated with decreases in agricultural output during the affected growing season, with only survey-based measures showing significant—and large—average losses ranging between 20–60% of pre-flood levels. We also combine multiple methodologies for measuring flood exposure to understand the distribution of agricultural impacts. Our results show varied experiences: households reporting direct flood-related harvest losses in communities where floods are detected lose up to 80% of their crop value while households living in the same community but not reporting direct losses are not significantly affected. We conclude with three recommendations for future research: (1) examine multiple metrics of flood exposure and understand their pros and cons, (2) align the empirical strategy and interpretation of results with the specific nature of what a given flood metric captures, and (3) conduct sensitivity analyses on outcomes of interest.