Expert judgments used to evaluate the deduplication algorithm used for constructing the OpenAIRE Research Graph. Each expert assigned each group with one of the following predetermined classes (that also indicate whether contained entities are equivalent or not): AMBIGUOUS: At least one DOIs is invalid (no metadata are available) (N/A) DELETED-DUPLICATES: DOIs once pointing to the same research object, currently deleted. (TRUE) MULTI-PUBLISHED: Article published in more than one locations (full or abstract) (TRUE) VERSIONS: Multiple versions of the same research object (e.g. pre-prints, post-prints etc). (TRUE) ERRONEOUS: Unrelated set of objects. (FALSE) PAPER-EXTENSIONS: Extended version of a conference paper in a journal. (FALSE) PART-OF-A-GROUP: Multiple parts of the same research object (e.g. multi-part publication, photos of the same collection etc). (FALSE) SUPPLEMENTARY: A publication and its supplementary material (including errata). (FALSE) The following are provided: OpenAIRE identifier Judgement Count of numbers in group DOIs in group