University for Continuing Education Krems Surveying irregular migrants: Challenges and approaches Key points • Irregular migrants are difficult to capture in statistics because of their absence from official sampling frames, mobility, and fear of detection. Surveying them requires tailored approaches, including non-probability sampling, trust-building strategies and ethical safeguards. • This chapter reviews three types of surveys that can yield data on irregular migrants: those that explicitly include them in the sampling design, those that target applicants of regularisation programmes, and retrospective surveys that reconstruct past legal trajectories. • Drawing on examples from France, Italy, Spain and the United States, this chapter shows how innovative designs and context-specific adaptations can improve coverage and data quality. • Each approach has its own strengths and limitations. A combination of methods, applied thoughtfully, is needed to strengthen the evidence base and support more accurate data collection and analysis. en TEXT book part Buchkapitel Capitolo di libro Text book part Text Buchkapitel Testo Capitolo di libro Surveying irregular migrants hard-to-count-population sampling methods Legal status trajectories Data challenges Mixed methods 2025-09-30 2025-09-30 Rocco Molinari Livia Elisa Ortensi University of Krems Press