Estimating uncounted migrants from innovative sources

The Estimating Uncounted Migrants from Innovative Sources (EstIMS-2) project aims to advance and operationalize statistical methods for estimating uncounted and irregular migrant populations across European Union (EU) countries within the European Statistical System (ESS). Building on prior research (notably CLANDESTINO, MIrreM and the EstIMS-1 project), the project focuses on improving the accuracy, comparability, and scalability of estimation approaches using both traditional and novel data sources. Over a 36-month period, the project develops and applies four complementary methodological strands. First, it enhances models combining official migrant stock statistics with digital trace data (such as social media) by addressing uncertainties, biases in administrative registers (including over-coverage from unrecorded emigration), and extending input data sources beyond single platforms. Second, it evaluates a methodology linking mortality records with population registers to infer uncounted migrant stocks, assessing feasibility, legal conditions, and applicability across multiple EU countries. Third, it explores extrapolation techniques based on auxiliary aggregated data (e.g., police and apprehension records), refining multiplier and regression-based methods and testing their transferability across national contexts. Finally, it integrates results from these independent estimation approaches, analysing their consistency and proposing methods to combine them into unified estimates with quantified uncertainty. The project produces a series of technical reports, country case studies, comparative analyses, and reproducible software tools to support implementation. By systematically evaluating data availability, methodological robustness, and cross-country comparability, EstIMS-2 aims to strengthen the evidence base and statistical capacity for measuring otherwise hidden migrant populations in Europe.