82 Brad K. Blitz registers. In some cases, the information provided by national governments reflects a considered approach to estimation: The statelessness figure is based on a Government estimate of individuals who . . . migrated to Côte d’Ivoire . . . and who did not establish their nationality at independence or before the nationality law changed in 1972. The estimate is derived in part from cases denied voter registration in 2010 because electoral authorities could not determine their nationality at the time . . .. The estimate does not include individuals of unknown parentage who were abandoned as children and who are not considered as nationals under Ivorian law.59 UNHCR also presented information in more user-friendly formats. Today, UNHCR’s website includes a versatile data builder that allows users to select variables and indicators in order to construct detailed tables using composite data from UNHCR’s operational and statistical activities, national sources, and other UN agencies and partners. Amid claims of greater accuracy, UNHCR explicitly privileged certain types and sources of data.60 Above all, it considered national censuses and population registers most useful, as Massey recommends: For such country-related information to be treated as accurate, it needs to be obtained from reliable and unbiased sources, preferably more than one. Thus, information sourced from State bodies directly involved in nationality mechanisms in the relevant State, or non-State actors which have built up expertise in monitoring or reviewing such matters, is preferred.61 There are several problems with this statement. First, it presumes that national censuses accurately record the status of individuals surveyed when, in practice, national censuses rely on self-completed questionnaires.62 Moreover, some states do not have a central population registry.63 Second, it fails to recognize how bias applies to all forms of data, including official information produced by state bodies. Third, it assumes that individuals have sufficient agency to obtain status and, equally important, that states will cooperate to recognize such claims. These challenges were acknowledged by the Conference of European Statisticians more than twelve years ago. 59 Ibid., p. 31. The main sources include (1) UNHCR’s statistical activities, which collate data from national sources and some UNHCR operations; (2) United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), which provides information limited to registered Palestine refugees under UNRWA’s mandate; (3) data provided by the Internal Displacement Monitoring Centre (IDMC), limited to people displaced within their country due to conflict or violence. 61 UNHCR, Handbook on Protection of Stateless Persons, p. 33. 62 Economic Commission for Europe, Difficult to Measure Census Topics, p. 5. 63 See Kerwin et al., “Statelessness in the United States.” 60 https://doi.org/10.1017/9781108914994 Published online by Cambridge University Press