Albert Kraler Albert Kraler Tuba Bircan Tuba Bircan Ann Singleton Ann Singleton University of Krems Press 2025 Key points • This chapter explores how ‘irregular migration’ is defined and why the concept is contested, showing the tension between using existing categories for measurement and critically interrogating them. • It highlights that terms such as ‘irregular’, ‘illegal’, or ‘undocumented’ are not neutral but historically and politically charged. • The chapter explains that ‘irregular migration’ may denote different phenomena, legal status, border crossings, or policy violations, and stresses the need for precise definitions. • It shows that irregularity is not fixed but shaped by laws, administrative practices, and political contexts, varying between states and over time. • Understanding irregular migration requires both snapshots of populations and trajectories of status change. The MIrreM taxonomy maps pathways into and out of irregularity, while making visible the limits of classification. PDFDocument eng 2025-09-30T07:06:59.455780Z 2025-09-30 Irregular migration Concepts legal status terminology reflexitivity mixed migration pathways in and out of irregularity missing migrants 585432 b application/pdf http://creativecommons.org/licenses/by-nc/4.0/