Big data for official migration statistics: Evidence from 29 national statistical institutions

International migration statistics suffer from extensive gaps and shortcomings. Recently, national statistical institutions (NSIs) have started using big data to complement traditional statistics, including on migration. Although these are promising developments, we still lack answers on the extent to which NSIs are currently using big data for migration and to what extent it complements the gaps in traditional data. We gathered data by interviewing experts from 29 NSIs to investigate how big data is used for official migration statistics. We show that 15 out of 29 NSIs either used big data for migration, had a pilot project or have been involved in joint initiatives. We reveal the specific implications of big data in human migration (e.g. internal mobility, stocks, flows and mobility patterns, among others and the most common sources used to extract official statistics). Moreover, we discuss the challenges and barriers preventing NSIs from using such data. Factors deterring countries from utilising big data include limited data accessibility, an absence of legal frameworks for big data usage, ethical concerns, the possession of already high-quality data, a deficit in expertise and methodologies and a lack of perceived necessity for supplementary data or approaches. Moreover, many countries did not know which data to use and were concerned about the quality and accuracy of such data. Legal barriers were more of an issue than the ethical aspects, and overall, participating countries believe that there is a high potential for big data in the future.