This year, for the first time, we have accounted for three types of returnees from Pakistan and Iran who found themselves in a situation of internal displacement once (back) in Afghanistan. We included 44,197 Afghans who were deported or voluntarily returned from Iran based on input from our sources in Afghanistan, including UN OCHA. This figure, approximately 10 per cent of the returns from Iran, is predominantly composed of young men who left Afghanistan in search of work and were considered displaced and in need of humanitarian assistance upon their return. We also included 285,951 individuals, who are part of a significant wave of returns from Pakistan. UNHCR estimates 48 per cent of returning refugees were not able to return to their place of origin. These people therefore fit the government’s definition of an internally displaced person. Finally, we have included a caseload of 22,559 undocumented Afghans who were forcibly deported from Pakistan back to Afghanistan. Given the involuntary nature of the return and the humanitarian needs of these individuals once back in Afghanistan, we consider them to be in a situation of internal displacement. Births and deaths in displacement We only account for births and deaths in displacement when our partners provide data. Given the shortage of disaggregated data and the fact that IDPs’ fertility and mortality rates may not correspond with national figures, we do not try to extrapolate births and deaths in displacement from national demographic data. Depending on the scale and duration of displacement, the lack of primary data on these flows can represent a potentially significant blind spot. In protracted crises such as Macedonia’s, reported changes in the size of the displaced population may depend more on demographic trends than on returns, local integration and settlement elsewhere, given the lack of progress in these areas. Total number of IDPs The inflows and outflows described above all influence the total number or “stock” of IDPs at a given moment in time – 31 December 2016 in the case of this report. We estimate the number of IDPs at the end of the year by triangulating data reported from one or more sources with a mathematically derived estimate based on the “flow” data available on new displacement, returns, local integration, settlement elsewhere, cross-border flight and births and deaths in displacement. We arrive at the total number of IDPs as of 31 December 2016 by taking the total at the end of 2015 and adding or subtracting flow data as follows: Total number of IDPsDec 2016 = Total number of IDPsDec 2015 + [Births2016 + new displacement2016] – [Returns2016 + settlement elsewhere2016 + local integration2016 + cross-border flight2016 + deaths2016] The equation is technically incomplete because it does not take into account the “counterflows” represented by failed returns, local integration and settlement elsewhere, or cross-border returns into displacement. Given, however, that data is not collected and these phenomena are accounted for as new rather than repeated displacement, the equation serves its purpose. In reality, the lack of coverage of the components of our data model and the way outflow data is aggregated mean the actual equation for most countries is often simply: Total number of IDPsDec 2016 = Total number of IDPsDec 2015 + New displacement2016 – Returns2016 The mathematical formula for estimating the stock of IDPs is at best a modelled approximation. We compare this with the data we obtain from our sources, and they do not always correspond. There are number of reasons for this: || The initial value – the estimate for the end of the previous year – is incorrect and needs to be revised. This occurs in Afghanistan, among other countries, due to the length of time it takes to verify displacement figures. || New displacement includes repeated displacement: This is the case every year in countries such as DRC or South Sudan, where pendular displacement – in which IDPs “commute” back and forth between their places of refuge and origin, often to tend to their land – generates higher numbers of displacements that often relate to the same people. METHODOLOGICAL ANNEX 99