Updating the LONELY-EU database of loneliness surveys: preregistered procedure for the yearly releases of the EU Loneliness Explorer

Preregistered procedure by which the LONELY-EU database of loneliness surveys (Deliverable 3.1, Horizon Europe Grant Agreement 101177225) is kept up to date: a yearly search of the latest publication year under the search protocol of Tang et al. (2025, https://doi.org/10.17605/OSF.IO/F9Y7Q), with the changes the pilot made necessary, the correction of existing rows from their codebooks, and an audit of every cell before each release. The procedure is research infrastructure built with artificial intelligence: calibrated classifiers and language models screen, code and audit under written rules, scripts check every output against the source documents, and every changed cell is logged with its basis. The database feeds the survey list of the EU Loneliness Explorer on the LONELY-EU website. The document reports the first application, to the publication year 2025, which produced release 2.0 of the database, and the audit of release 2.0. Every future update follows this procedure, with code, briefs and coding manual public at https://github.com/arturobertero/LONELY-EU_D3.1. Each release is published in the EU Loneliness Explorer and the LONELY-EU Data Tools with its change log; the database itself is not deposited here.