An investigation into the factor structure of the Health of the Nation Outcome Scales for People with Learning Disabilities.

Abstract

The Health of the Nation Outcome Scales for People with Learning Disabilities (HoNOS-LD) is one of the most used outcome measures in learning disability services in the United Kingdom. There is relatively little known of the psychometric properties of the scales. A data set of HoNOS-LD scales from 571 people with learning disabilities was randomly split into two halves. Exploratory Mokken analysis was applied to the first dataset, and confirmatory scale factor analysis was applied to the second dataset to test the fit of scale structures. Two-factor and three-factor solutions were explored in the Mokken analysis, with the three-factor option having somewhat better characteristics. One-factor, three-factor and seven-factor solutions were explored using confirmatory factor analysis; a three-factor solution with items 8, 16, 17 and 18 used separately offers the best characteristics. The HoNOS-LD is best conceptualised as consisting of three scales, accounting for 14 items that can be labelled as 'Cognitive and Physical Functioning', 'Behaviour and Mood Disturbances' and 'Functional Difficulties'.