What are good quality data on a phenomenon that is hard to measure?
Policymakers often point to data to justify their decisions, particularly in contested policy spaces, such as immigration. Irregular migration, while a point in case, poses distinct challenges to this practice.
Although irregular migrants are the subject of intense political and media scrutiny in many countries, information about them is notoriously scant and unreliable. This book chapter examines what constitutes “good quality” data in the complex landscape. It introduces the MIrreM framework for assessing irregular migration estimates and indicators and discusses how uncertainty and other criteria shape data quality. Rather than assuming these figures are fit for purpose, we suggest users interrogate them, asking whether the data are credible, transparent, and suited to question at hand. We conclude with a checklist based on the five MIrreM criteria to support this process.
Publication details: Kierans, D., & Siruno, L. (2025). What are good quality data on a phenomenon that is hard to measure? In D. Kierans & A. Kraler (Eds.), Handbook on Irregular Migration Data. Concepts, Methods and Practices (pp. 55-64). University of Krems Press. https://doi.org/10.48341/g31s-vq79