Rasch analysis of the Nottingham extended activities of daily living scale.

BACKGROUND AND PURPOSE The Nottingham Extended Activities of Daily Living (EADL) Scale is frequently used in clinical practice and research in rehabilitation to assess patients’ independence in activities of daily living. Summative scores are used for this purpose, but this is problematic because the EADL is an ordinal level measurement scale. OBJECTIVES To examine the fit of data to the Rasch model and to determine how the fit could be improved by making changes to the scale. The appropriateness of using total and subscale (Mobility, Kitchen, Domestic and Leisure) scores in determining change over time was evaluated. METHODS EADL data (n = 210 stroke patients, 55% male, age range 27–93 years) from a randomized trial of a Stroke family support organiser service were analysed using the Partial Credit model. RESULTS Rasch analysis did not support the total scale as a unidimensional measure of activities of daily living. However,the subscales exhibited reasonable fit to the Rasch model following re-scoring and removal of items. Item 16 exhibited differential item functioning for age and item 22 differential item functioning for gender. CONCLUSION The results endorse the use and psychometric properties of the 4 EADL subscales, but not the total scale.Further work to corroborate these findings would be useful.