Denis Kierans Denis Kierans Albert Kraler Albert Kraler University of Krems Press 2025 Key points • Irregular migration data are often of low quality and misinterpreted by those who use it, when they are used at all. This Handbook provides clear and easy-to-understand guidance on how to improve the quality of these data and an understanding of them. • Despite ongoing public and political interest, there has been a notable lack of investment in improving the methods and capacities for generating irregular migration estimates, particularly in European National Statistical Offices (NSOs). By synthesising key findings from the MIrreM project and highlighting good practices and promising innovations, this Handbook seeks to help bridge that gap. • Ultimately, this Handbook makes the case that these challenges can only be met – and much risk mitigated in the process – through strengthened leadership on, coordination around and long-term investment in a Europe-wide infrastructure capable of producing, disseminating and fostering responsible and appropriate use of irregular migration data PDFDocument eng 2025-09-30T06:55:42.664660Z 2025-09-30 Irregular migration history Europe Migration statistics Data collection 364983 b application/pdf http://creativecommons.org/licenses/by-nc/4.0/