ABSTRACT Overstayers—travellers entering a country with a valid visa but staying beyond the initially authorised period—are a blind spot of migration research. Past studies claim that overstaying is indeed the main gateway to irregular migration in Europe, but few estimates exist. This paper explores three new methods to estimate the inflows of overstayers. We concentrate on the Schengen area as destination, given its relevance in global migration flows, and on non‐European countries as origins, since for travellers from these countries commercial flights are the most likely transportation mode to Europe. Our methods rely on aggregate information on incoming and departing passengers from all airports in the Schengen Area, and on Facebook users' mobility data. In the first method, we compute ‘net air travel flows’ as the difference between incoming and outgoing passengers; we then deduce net regular migration (using data from Eurostat and the QuantMig project) from ‘net air travel flows’ to obtain ‘unaccounted net flows’, which we hold to equate approximately to newly incoming overstayers with short‐stay visas for 2019. In the second method, building on the first estimate, we employ the logic of gravity models to project estimates for later years. In the third method, we build on the intuitions of the first method but use net migration figures from data on Facebook users' cross‐border movements. Substantively, the results of the different methods converge, indicating around 450,000 new overstayers who entered the whole of the Schengen Area in 2019 with short‐stay visas. Analyses for the following years obtained with the second and third method match and are in line with changes in travel policies during the COVID‐19 pandemic (2020 and 2021), suggesting a significant reduction in the number of overstayers for those years and an uptick for the years 2022–2023. By uncovering the size and scope of the overstaying population we shed light on a highly contested issue in the public debate and ultimately contribute to raise awareness on the constructed nature of the ‘regular’ versus ‘irregular’ framing of migration.
Recchi et al. (Thu,) studied this question.