Denis Kierans Denis Kierans Albert Kraler Albert Kraler University of Krems Press 2025 This Handbook brings together concepts, findings, methods, and case studies to offer a clear, practical understanding of irregular migration data. It addresses the challenges of conceptualising, measuring, interrogating, and using data on one of Europe’s most politically sensitive migration issues. Drawing on examples from across Europe and beyond, it provides guidance on concepts and definitions, ethics, estimation methods, data innovation, and policy application. It is designed to support policymakers, practitioners and researchers seeking more informed, transparent, and coordinated approaches to irregular migration data. PDFDocument eng 2025-09-10T07:58:30.699338Z 2025-09-10 irregular migration measurement concepts statistical data estimation methods data ethics data quality register data informal work 6312433 b application/pdf http://creativecommons.org/licenses/by-nc/4.0/