# **1 Introduction**

Household surveys are the dominant tool to measure and monitor welfare in low- and middle-income countries. In these contexts, measures of material well-being typically consider a combination of household consumption and expenditures, of which food comprises a large share. Indeed, global monitoring of extreme poverty relies on food-based estimates of welfare, such as the Cost of Basic Needs approach. Proxy means-tested targeting of interventions also derives from these estimates of welfare. Many programs worldwide target food consumption and nutrition, ranging from school meals to food subsidies like the Supplemental Nutrition Assistance Program (SNAP). Because of its centrality to policy and welfare measurement, a large body of the literature has questioned the accuracy of different modes of collecting consumption data to assess household well-being. We revisit this issue at a time when developing countries have increasingly moved to recall modes to collect food consumption in their national expenditure surveys.

Acquisition diaries have become the workhorse for benchmarking comparisons of household measurements from alternative collection modes. Beegle et al. (2012) randomize households in Tanzania to individual assisted diaries to define a benchmark against alternative survey designs that use recall questions. This is possibly the most important experiment on consumption measurement in low- and middle-income countries in the last decade (a more recent study for Niger is Backiny-Yetna et al., 2017). The accuracy of consumption measurements is also of concern in the developed world. For example, Brzozowski et al. (2017) compare recall questions on food spending from the Canadian Food Expenditure Survey to data from expenditure diaries. Battistin and Padula (2016), among others, do so using the Consumer Expenditure Surveys in the United States. In these instances, too, the accuracy of reports is assessed against diaries.

The assumption that diaries provide an error-free benchmark has little statistical justification. Diaries arguably minimize various types of reporting errors, including recall errors, telescoping, rule of thumb, and errors of omission (Lyberg and Kasprzyk, 2004). However, diaries are far from perfect. Most diary surveys are characterized by differences in reporting within the interview period, usually with a declining pattern over time (Silberstein and Scott, 2004). Possible explanations are not only declining cooperation due to fatigue but also the tendency of participants to deviate from the usual purchasing behavior as an effect of the diary or social pressure (Peterson Zwane et al., 2011). The proxy reporting of events experienced by persons other than the respondent yields figures different from those obtained from individual diaries (Beegle et al., 2012). The ratio between food totals computed from household surveys using diaries and national accounts have been found to be considerably low (Gieseman, 1987, and Bee et al., 2013). Moreover, diaries are expensive, as completion involves a reasonable standard of literacy and commitment, and regular visits from interviewers to ensure quality standards boost costs.

Faced with high costs of implementation, respondent fatigue, the need for enumerator effort, and the risks of enumerator shirking, many developing countries have moved to collecting recall data.<sup>1</sup> In recall interviews, households are typically asked to report on food _consumption_ during the specified period and

> 1The World Bank’s Living Standards Measurement Study (LSMS) survey finder includes a list of household consumption and expenditure surveys: of almost 90 surveys from more than 25 countries, more than 75 use recall. See also the guidelines on the use of recall interviews endorsed by the United Nations Statistical Commission (FAO and The World Bank, 2018).

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