case of Cereals, Dairy, and Meals Out do the 14-day recall values exceed the benchmark values; for all others, they are lower, often significantly so.

The 7-day subset list (module 3) tends to report greater positive value errors than the 7-day long list, which must derive from the module’s focus on only the most commonly consumed items because that is the only design feature that distinguishes the two modules. In contrast, the collapsed list exhibits both overreporting and underreporting.

It is not clear what causes these value error patterns. Overreporting could occur if the value of salient episodes of consumption is telescoped into the recall period; presumably, salient episodes are constituted by larger consumption values. Equally plausible is that respondents do not value each and every individual consumption event, but use a rule of thumb to do so. Overreporting could then also occur if larger (and therefore more salient) episodes are used as the rule of thumb. The fact that reporting errors on some key food groups (such as Tubers, Sugars, Vegetables, and Fruits) switch from positive to negative as the recall period shifts from 7 to 14 days suggests one of two possibilities depending on what underlies the reporting behavior: (1) the negative influence of recall error outweighs the positive influence of telescoping as the recall period extends in length from 7 to 14 days, whereas telescoping dominates in the shorter period; (2) alternatively, if rule of thumb reporting is utilized for both periods, rule of thumb tends to overreport to a greater degree during a shorter recall period.

A different reporting pattern is evident for the usual month. While this module recorded a higher consumption incidence on most food groups (significantly higher than the benchmark in all but two cases), the values recorded in this module design are significantly lower, with the sole exception of Cereals, for which the value reported is not significantly different than the benchmark. It appears that the particular cognitive challenges of the usual month approach, at least in a highly seasonal setting such as rural Tanzania where consumption patterns can vary widely throughout the year, consistently result in overestimation of consumption incidence on most foods and in an underestimation of value.

The two household diaries exhibit a distinct pattern of value reporting error. Because the expected main driver of reporting error between the household diary and the personal diary would be the inability to capture personal consumption outside the home fully, the values reported should diverge most for the relevant food goods. This is indeed what we find. The household diaries record 36 percent – 39 percent lower value in Fruit consumption, 37 percent–42 percent lower value in Beverages, and 35 percent – 36 percent lower value in Meals Outside the Home. In contrast, Cereals, Tubers, and other basic foodstuffs are closer in value to the benchmark, although significantly lower at times, for the frequently supervised household diary. The higher consumption values for the infrequently supervised diary relative to the frequently supervised diary may suggest the partial presence of telescoping or rule of thumb errors (similar to what we observe with the 7-day recall) if, indeed, the infrequently supervised diary defaults to a shortperiod recall survey as a result of less frequent updating of the diary.

Table 6 summarizes how consumption value reporting error covaries with particular household characteristics by listing the precisely estimated interaction terms as given by equation (3).<sup>15</sup> The characteristics of households do mediate the degree of error in the value reported, although the patterns are less clear than in the case of consumption incidence. One fairly clear result concerns the number of adults

> 15 Appendix table 3 relays the magnitude of all estimated interaction terms.

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