The aim of this study was to investigate the contribution that rating scales can make to the understanding of the behaviour of people with dementia in a residential unit The participants were thirty eight residents in a Special Dementia Unit (SDU) organised as a hostel. Scores were recorded at staff meetings for the following scales: Crichton Royal Behavioural Rating Scale (CRBRS), Confusion Rating (CR), Barthel Index (BI), Cohen‐Mansfield Agitation Inventory (CMAI) and the Mini Mental State Examination (MMSE). It was found that the CRBRS and the CR provide a useful reference to mental and physical disabilities. Scores from the CMAI recorded the type, the frequency and the number of agitated behaviours displayed by individual residents. The majority of agitated behaviours belonged to the physically non‐aggressive category. Information from these scores was combined to construct residents' profiles. We concluded that the CRBRS, the CR and the CMAI can provide information about residents, both as individuals and as a group, which can assist in the understanding of behaviour and in the evaluation of the function of an SDU.