Methods of household consumption measurement through surveys: Experimental results from Tanzania

Surveys of consumption expenditure vary widely across many dimensions, including the level of reporting, the length of the reference period, and the degree of commodity detail. These variations occur both across countries and also over time within countries, with little current understanding of the implications of such changes for spatially and temporally consistent measurement of household consumption and poverty. A field experiment in Tanzania tests eight alternative methods of measuring household consumption, finding significant differences between consumption reported by the benchmark personal diary and other diary and recall formats. Under-reporting is particularly apparent for illiterate households and for urban respondents completing household diaries; recall modules measure lower consumption than a personal diary, with larger gaps among poorer households and for households with more adult members. Variations in reporting accuracy by household characteristics are also discussed and differences in measured poverty as a result of survey design are explored.