Seasonal bias in household vulnerability to poverty stimates: insights from a natural experiment

Using data from 260 households from the Hadejia-Nguru wetlands, the paper shows that vulnerability to poverty estimates are biased if the data used is seasonal. The seasonal bias in the consumption expenditure is less pronounced than in its variance. The paper further shows that the relative sizes of the seasonal bias in expected consumption expenditure and its variance determines the final magnitude of the bias. However, the bias in the expected consumption expenditure is sufficiently corrected by including seasonal dummy variables. We therefore encourage researchers to consider seasonality when they are modelling consumption expenditure with the aim of estimating vulnerability.