The Behavioural Assessment Scale: internal consistency and factor structure for an elderly psychiatric population

The subscales of the Behavioural Assessment Scale (BAS) (Language, Mobility, Physical Independence, Occupation and Orientation, and Social Integration) were designed to measure specific areas of functioning. The purpose of this investigation was to assess the psychometric structure of the BAS in a sample of 275 geriatric psychiatry inpatients. This psychometric assessment was carried out using 2 methods: measures of internal consistency and exploratory factor analysis. The measures of internal consistency suggested that only the Language and Physical Independence subscales measured a unified construct. The subsequent factor analysis revealed 3 highly correlated factors that accounted for 65% of the item variance. These factors were interpreted as Daily Living Skills, Communication/Social Skills, and Problem Behavior. The high intercorrelations between the factors were interpreted as a general sensitivity of the BAS to global decline in functioning associated with dementia (i.e., severity of illness). The computation of factor-based subscales and a general functioning aggregate were recommended for clinical use of the BAS.