enumeration area, EA) was chosen within the village through simple random sampling.<sup>14</sup> In the selected EA, all households were listed. From these lists three households were randomly assigned to each of the eight modules. This was done through simple random sampling starting with module 1 and moving to module 8. The five alternative recall questionnaires were conducted in the span of the 14 days the survey team was in the EA to conduct the household diaries. Fortunately refusal and attrition after starting the survey are not an issue. Among the original households selected for the survey and assigned to a module, there were 13 replacements due to refusals. Three households that started a diary were dropped because they did not complete their final interview. This yields a final sample size of 4,029 households.<sup>15,16,17</sup> The basic characteristics of the sampled households generally match the nationally representative data from the Household Budget Survey (2006/07) (results not presented here but available from the authors upon request). Household interviews were conducted over a 12-month period, but because of relatively small samples within the period, we do not explore the survey assignment effects across seasons. Instead, the analysis reports the mean effect of questionnaire design across all seasons in Tanzania since each season is equally weighted in the data.

The randomized assignment of households to different questionnaire variants appears to have been successful when examining a set of core household characteristics, presented in Appendix Table 1, in terms of balance across characteristics relevant for consumption and consumption measurement. The table presents these mean characteristics by each module. At any point where there is a significantly different pairwise comparison, those pairs are indicated. Out of a possible 420 pairwise comparisons in Appendix Table 1, only 13 pairs are significantly different at the 5 percent level.

14 The equivalent of a village in urban areas is the _mtaa_ (Swahili for “street”). As there is no official subdivision of an _mtaa_ , our listing teams carefully defined and delineated Enumeration Areas within the _mtaa_ in cooperation with local informants.

15 Interviewers were trained extensively and were under continuous quality control. Regular supervisor re-interviews of households as well as supervisory direct observations were made to prevent any interviewer idiosyncrasies from developing. Each interviewer implemented all eight modules in equal proportion in order not to confound module effects with interviewer effects. There is the possibility of spillover effects in that an interviewer may influence how one module is completed based on experience with another module. Such learning and spillovers may also exist in other surveys, where experienced interviewers have exposure to different consumption modules. To the extent that such an effect may exist, it would be expected to result is an underestimation of any real gap between consumption collected by alternatively designed modules. However, this design was selected by investigators to minimize the presumed more serious risk of interviewer effects confounding the estimated module effects that can occur if individual interviewers were exclusively assigned to one module type.

16 The experiment used double blind data entry and high levels of quality control to reduce any effect of data entry on estimated cross-module differences. The data entry protocol was the same for all versions of the questionnaire and hence should not be a source of systematic error biasing the comparison of module performance. 17 We have almost no item non-response (in that the respondent does not report that the household consumed the specific item in the specified period) for food in the recall modules or for non-food in any of the modules. We do not observe any distinct patterns in non-response across our survey designs, or within a recall design by the location of the item on the list.