Measuring Poverty in Tanzania : Comparison of Diary and Recall Approaches to Food Consumption Data Collection

Consumption data from household surveys continue to be the main source for poverty and inequality statistics in low- and middle-income countries. Although recent research has demonstrated that the choice of diary- versus recall-based methods for consumption data collection can directly impact poverty measurement, the available evidence stems from small-scale, subnational survey experiments. This study uses data from a nationally representative randomized survey experiment in Tanzania to provide a comparative assessment of how household consumption and poverty measures may be impacted by relying on a 14-day food consumption diary versus two different variants of 7-day-recall-based food consumption data collection. The analysis reveals significant differences in food consumption expenditures across the diary and recall arms, and these differences result in differences in total consumption expenditures as well. The results further show that the diary method captures more diverse food consumption items, but the overall consumption expenditure appears significantly lower than in the recall arms, even at different percentiles. Despite these disparities, the paper finds little statistically significant difference in poverty rates between the diary and recall arms, even at different thresholds.