When places close but data does not: validating the temporal information in Foursquare OS Places and OpenStreetMap against official registers

Open point-of-interest (POI) datasets increasingly carry temporal information, yet none of it has been validated. Foursquare OS Places attaches creation and closure dates to over 100 million places and now feeds Overture Maps Places, but no study has evaluated these fields. We report the first validation of POI temporal information against official registers, using Japan as the testbed. Four license-clean reference systems with day-precision event dates (health-insurance facility registers, the complete Japan Post office ledger, large-store notifications, and 3,789 chain-store openings from corporate press) are linked to Foursquare and to full-history OpenStreetMap by an audited procedure with approximately 94.5% precision. Closure is a systematic blind spot on both platforms: even in mature matched subsets, Foursquare records at most 3.6-20% of registered closures, and 92-96% of closed post offices persist in OpenStreetMap. Recorded timestamps are nonetheless accurate to days or weeks, and incorporation is strongly stratified between chains and independents. We release the protocol, reference datasets, and matched pairs for reuse. This preprint has been submitted to Scientific Data for peer review.