By Jose L. Ayuso-Mateos (UAM), Laura Rico (UAM) and Andreas J. Weser (NTNU)

One of the SYNCHROS-teams focuses on the mapping of the international landscape of cohorts. This landscape is scattered across the globe and a multitude of different types and sizes of cohorts has to be considered. It covers – for example – patient- and population-cohorts, and clinical trials. Their quality and size vary from a few dozen participants in the case of clinical trials up to millions for population cohorts. Hence, clear definitions, exclusion and inclusion criteria are needed, as well as precise search-terms for data base queries. Under the lead of the Universidad Autónoma de Madrid, and thanks to numerous expert-consultations a methodology for the mapping of different types of cohort initiatives could be developed and enriched by different points of view. This is an essential prerequisite to elaborate a comprehensive report on the European and international landscape of population-based cohorts, patient cohorts and control trials that is accepted and useful for a broad community of stakeholders.