Present in consortia, rarely in the lead: Swiss and UK participation in Horizon Europe during non-association, a descriptive analysis of CORDIS project data, 2014-2025

Switzerland (calls 2021-2024) and the United Kingdom (calls 2021-2023) took part in Horizon Europe as non-associated third countries before associating. Their organisations were generally not eligible to sign grant agreements as EU-funded beneficiaries, with exceptions, and UK entities generally could not coordinate Pillar 2 grants, subject to exceptional eligibility and directly awarded grants (6 of the 7 recorded UK Pillar 2 coordinations match an exception route). This paper describes their participation and coordinator roles in collaborative projects, using the full CORDIS project and organisation tables for Horizon 2020 and Horizon Europe (208,183 organisation rows, call years 2014-2025). The design was pre-registered; in the author's version history, which is not public, the registration precedes every recorded outcome script and output, but readers cannot verify this and the record cannot exclude inspection outside it. The registered primary estimate, a difference in differences of log participation share against Norway and Israel, is -1.1% for Switzerland (95% placebo interval -27.0% to +11.0%) and -30.3% for the UK (-46.9% to -23.1%). Neither is read as an effect of non-association: a registered placebo-date test shows a UK decline of the same size between 2017-2018 and 2019-2020, and the control group failed its own stability test. Coordinator roles fell to 1-5 per call year in each country, from 15-48 Swiss and 44-107 UK coordinations per year in 2017-2020; of the 18 that remained (9 per country), 13 match a documented eligibility route and 5 do not. In Horizon Europe projects that share partners with a Swiss- or UK-coordinated Horizon 2020 project, fewer than 1% had a Swiss or UK coordinator, against 12% under the same rule for five small EU states. After association, the UK coordinator share returned to about 5%; 2025 Swiss data are too recent to judge.