Comparing statistics on migration across countries is difficult when countries and even international organisations use different definitions of an international migrant. For example, 2020 UNDESA data, which identify international migrants based on country of birth, estimate that 3,60% of the world’s population are migrants (IOM, 2021d) while the World Bank’s 2023 World Development Report (World Bank, 2023), which identifies international migrants based on country of citizenship estimates that migrants represent 2,30% of the world’s population. However, citizenship data fail to account for the many migrants who left their country of birth and were naturalized in a destination country (thereby preventing an understanding of long-term migration or integration) or for migrants with multiple citizenships.
Figure 2:
Another example is the disparity between Statistics Norway and United Nations High Commissioner for Refugees (UNHCR)'s figures for the number of refugees in Norway in 2015, the former demonstrating almost 100,000 more refugees than the latter. This is because UNHCR's figures are based on the number of asylum seekers who have been granted residence in the country over a ten-year period, after which it is assumed that a lasting solution has been found or that the person has been resettled (Statistics Norway, 2017). Discrepancies such as these many contribute to different understandings of the prevalence, characteristics, welfare and contribution of migrant groups.