Abstract The different ways in which diagnoses may be categorized in EQA schemes are considered. They may be grouped in very large diagnostic categories, or in narrow specific diagnoses. They may be categorized as dangerous or non-dangerous diagnoses. They may be categorized by the participants or a panel of experts. They may be categorized according to organ system, but rarely by underlying pathological process. The ways in which these categories are reached is considered, and the effect this has on the educational role of EQA schemes. This categorization will also influence the participant's strategy to ensure that they are not categorized as a poor performer.