NGOs. Initiatives such as JIPS, a collaborative project of UN and NGO actors, have also been established to support governments and operational organizations to design and implement data collection processes.

There are a variety of data sources for generating statistics on forced displacement, each of which has strengths and weaknesses. Despite the significant challenges, large amounts of data are collected and disseminated every year. The main data sources and methods for the generation of statistics on forcibly displaced populations include: (a) registration of refugees and asylum-seekers; (b) registration of IDPs; (c) profiling of IDPs; (d) population movement tracking systems; (e) national population censuses; (f) sample surveys; (g) border crossings; (h) administrative records and registers; (i) general population registers; and (j) a variety of estimation methods for producing statistics when adequate and reliable data on individuals are unavailable (UNSD 2014).

Several of these data sources might be used together to triangulate estimates of stocks and flows for a particular displacement situation. Some data sources (such as registration systems and population censuses) are more appropriate for estimating stocks of asylum-seekers, refugees and IDPs at a particular point in time, while other data sources (such as population tracking systems and border crossings) are more appropriate for estimating flows over a specific period. In general, there is a lack of comprehensive and up-to-date data available on all stocks and flows for a particular displacement situation (see Table 4). Consequently, data on flows might be used to estimate stocks, for example in the absence of government data, the stock of refugees in many industrialized countries is estimated by UNHCR based on 10 years of individual asylum-seeker recognition. And, especially in the case of IDPs, changes in the total population combined with some contextual analysis, may be used to deduce estimates of new internal displacement or returns. However, these approximations are flawed unless data on all other flows (births, deaths, repatriation etc.) are also available, which is not usually the case. Even a static figure for the stock of IDPs in a particular location might obscure substantial flows including new displacement and returns. Moreover, there are no common definitions of the various stocks and flows, and therefore the risk of double counting or gaps cannot be discounted. For example, IDPs who subsequently cross international borders may be counted as both IDPs and refugees (e.g. in the case of the Syrian displacement crisis).

**Table 4: Stocks and Flows**

|**Stock**|**Increas**|**es**|**Decrea**|**ses**|
|---|---|---|---|---|
|**Asylum-**<br>**seekers**||New applications for asylum,<br>separately identifying individuals<br>who were previously IDPs|<br><br>|Positive decisions (convention<br>status, complementary protection<br>status)<br>Rejected<br>Otherwise closed|
|**Refugees**|<br><br><br>|Spontaneous arrivals (group<br>recognition, temporary protection,<br>individual recognition)_, separately_<br>_identifying individuals who were_<br>_previously IDPs_<br>Resettlement arrivals<br>Births<br>Administrative corrections|<br><br><br><br><br>|Repatriation<br>Resettlement<br>Cessation<br>Naturalization<br>Deaths<br>Administrative corrections|
|**IDPs**|<br><br>|New internal displacement<br>Births<br>Administrative corrections|<br><br><br><br>|Cross border flight, becoming an<br>asylum-seeker or refugee<br>Return<br>Settlement elsewhere in the country<br>Local integration<br>Administrative corrections|

_Source_ : UNHCR Global Trends, IDMC Forced Displacement Data Model