Measuring the care needs of young people with intellectual difficulties: Construct validity of the learning disability vulnerability assessment scale and utility in establish the care needs of young people

The concept of 'vulnerability' in children is critical to needs-related planning and risk management. Despite proliferation of measures there is limited evidence-base to support the validity of existing, relevant clinical assessments. The FACE CARAS young person's risk assessment toolkit includes a measure of vulnerability-the Learning Disability Vulnerability Assessment Scale (LD-VAS). Good inter-rater reliability has been reported but construct validity has not previously been demonstrated. The aims of this study were to assess the construct-validity of the tool by: (i) evaluating the dimensionality of the ratings produced, and (ii) modelling the ability of the scores to quantify the care needs of young people. LD-VAS ratings were available for 143 young people, the dimensionality of the scale ratings was assessed using a parallel analysis and confirmatory factor analysis (CFA). The ability of scores to predict care-level was modelled using discriminant function analysis and multinomial logistic regression. A single factor CFA model showed a good fit to the data. The discriminant function analysis suggested several scoring profiles exist, relating to care-level. On multinomial logistic regression the scores could statistically significantly differentiate between those in the lowest and higher intensity care categories. The LD-VAS appears to have construct validity and is potentially useful in supporting rational decision-making regarding care-provision for children affected by learning disability.