The remainder of the paper is organized as follows. Section 2 will discuss the different methods commonly used to measure hunger, while Section 3 walks through a number of errors that can be expected when measuring hunger directly from HCES and how some of these errors likely differ by survey design. Section 4 introduces the data and experimental set-up. Section 5 quantifies differences in hunger numbers across the various arms of the survey experiment and verifies whether the magnitude of these differences is orthogonal to household characteristics. Section 6 presents a concluding discussion on how our results can be used to inform debates about measuring hunger through household surveys.

# **2. METHODS OF MEASURING HUNGER**

The most widely publicized method of calculating global hunger is the one used by the Food and Agriculture Organization (FAO) of the United Nations in a series of reports tracking world hunger, with FAO (2012) being the latest. More recently, the FAO indicator is used to track progress toward the first Millennium Development Goal of halving poverty and hunger by 2015. It relies on the assumption that the supply of food energy follows a log-normal distribution, which can be parameterized by a mean and a coefficient of variation (CV) – to capture the food access distribution. It calculates the mean from Food Balance Sheets (FBS), adding national food production and imports and subtracting exports, food losses, food used for seeds, animal feed, and stock changes to calculate the total availability of food in a country.<sup>2</sup> Combining this with population data allows the FAO to estimate the total kilo calories available for human consumption per person, per country in a particular year. The CV is calculated from a limited number of HCES.<sup>3</sup> For most countries the CV was kept constant across years and only the mean was revised.<sup>4</sup> Finally, the FAO estimates the required energy of a population by determining age-sex specific minimum daily energy requirements under the assumption of ‘light work’. These numbers are aggregated to yield the requirement of an average person. The area underneath the log-normal energy

> 2 Available at http://faostat3.fao.org/home/index.html (accessed 11 June 2013)

> 3 Smith (1998) reports that, at the time, for 18 out of the 99 countries, the CVs are estimated based on analysis of nationally representative HCES. The rest of the countries’ CVs are predicted either from measures of income distribution or as the mean CV estimated for other countries in the same region. The CVs were then also assumed not to change over the twenty-year period for which undernourishment estimates are undertaken.

> 4 In 2012 the FAO revised its distribution to be the skew-normal distribution (Azzalini, 1985), which generalises the normal distribution to allow for skewing. The FAO now uses survey data to calculate the CV and coefficient of skewness. This revision also took into account the average physical stature of each age-sex group derived from DHS data. The FAO updated the CV estimate for 37 countries, and, for the other countries (where they did not obtain HCEs), they used the same CV as in the past.

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