Other effective area-based conservation measures (OECMs) are sites outside protected areas that deliver effective and long-term in situ conservation of biodiversity. Biodiversity conservation may be the primary objective of the site, a secondary objective of a site that is managed for other purposes, or it may be an unintended consequence of the way the site is managed. OECMs may be governed and managed by governments, private entities or Indigenous peoples and local communities, or a combination of these. This tool guides an assessor through three steps to apply eight criteria which determine if a site qualifies as an OECM as set out under the Convention on Biological Diversity. For sites which do not currently meet all the criteria, the tool serves to highlight areas where further information or improvements in governance and management are required.