Research-focused information systems harvest and promote the scientific output of researchers. Disambiguating author identities is key when disentangling homonyms to avoid merging several persons' records. ORCID offers an identifier to link one's identity, affiliations, and bibliography. While funding agencies and scholarly publishers promote ORCID, little is known about its adoption rate. We introduce a method to quantify ORCID adoption according to researchers' discipline and occupation in a higher-education organisation. We semi-automatically matched the 6,607 staff members affiliated to the 145 labs of the Toulouse scientific area with the 7.3 million profiles at orcid.org. The observed ORCID adoption of 41.8% comes with disciplinewise disparities. Unexpectedly, only 48.3% of all profiles listed at least one work and profiles with no works might just have been created to get an identifier. Those 'empty' profiles are of little interest for the entity disambiguation task. To our knowledge, this is the first study of ORCID adoption at the scale of a multidisciplinary scientific metropole. This method is replicable and future studies can target other cases to contrast the dynamics of ORCID adoption worldwide.