p�,�,�,� , the median price of item k in the reference strata in the reference month. Two sets of price deflators were calculated, one for food and another for nonfood items, the nonfood price deflator was used to deflate the consumption flow of durable goods.

## Poverty Line

Determining a household’s poverty status requires a poverty line against which to compare consumption. A poverty line serves as a reference point for what might be an acceptable minimum standard of well‐being, below which one could be considered deprived, or living in poverty (Ravallion, 2017, 1998). The choice of the poverty line considers what might constitute an acceptable minimum standard of living and the potential impact of resulting poverty estimates on policy decisions. Once a poverty line has been chosen, poverty analysis is then typically based on comparing the first three poverty measures of the Foster‐Green‐Thorbecke (FGT) class of poverty indicators. FGT measures consist essentially of variations of specification 0, where the parameter α takes the value of 0 for the poverty headcount, 1 for the poverty gap, and 2 for poverty severity (Foster et al., 1984).

Where y� denotes the consumption y of individual i , n denotes the total population, and z the poverty line.

Theoretically, a national poverty line could have been estimated for South Sudan in the year 2016 using the survey data. However, the international poverty line of US$1.90 PPP was chosen.<sup>32</sup> Given that the international poverty line was based on the predicted poverty line for the world’s 15 poorest countries, combined with the expectation that poverty in South Sudan was to be relatively high, the international poverty line was considered an appropriate metric, also offering the ability to make international comparisons. Hence, the $1.90 USD PPP (2011) poverty line was first converted into current SSP and adjusted to reflect South Sudanese purchasing power using the South Sudan PPP conversion factor for 2011. It was then adjusted for inflation up to October 2016 using the national CPI calculated by the National Bureau of Statistics, resulting in a value of approximately 65 SSP (October 2016).

# 4. Results from the HFS

In 2016, more than 4 in 5 South Sudanese people in the seven states covered in the HFS lived under the international poverty line of US$1.90 PPP (2011) per capita per day. The poverty headcount was equal to 83 percent in 2016, with a 95 percent confidence interval from 81 to 85 percent. These levels of poverty place South Sudan among some of the poorest countries in the world. South Sudan’s poverty headcount ratio is much higher than the average estimates of other countries at similar levels of development (Figure 3). The estimated poverty headcount ratio is not particularly sensitive to the choice of poverty line, since average consumption levels are so low that the poverty line lies at a point where the slope of the cumulative distribution of consumption tapers off (Figure 5). The deterioration of economic conditions has driven many poor households down to hardship conditions (Figure ). The poverty gap, which measures poor households’ average deficit in consumption relative to the poverty line, is equal to 47 percent in 2016. The average poor household is therefore consuming about one‐half of the poverty line in 2016 (US$ 1.00

> 32 The international poverty line was first introduced in the 1990 World Bank World Development Report with the intent of measuring poverty across countries in a consistent manner. This international poverty line used data on 33 national poverty lines for the 1970s and 1980s and represented the predicted poverty line for the poorest country in the sample, equal to about $0.76 USD PPP (1985). The international poverty line was subsequently adjusted for inflation as new sets of PPP were made available through the International Comparison Program. The computation of the current international poverty line of $1.90 USD PPP per day was obtained as the unweighted average of the poverty line for the 15 poorest countries, as such: i) by adjusting the national poverty lines of the 15 poorest countries for inflation up to 2011; ii) then converting the national poverty lines to real USD using the 2011 PPPs; and iii) then computing the simple average of the 15 national poverty lines. The resulting average poverty line is equal to $1.88 USD PPP (2011) per person per day, which was rounded up to $1.90 USD PPP (2011).

13