The validity, reliability and responsiveness of the Nottingham Extended Activities of Daily Living scale in patients undergoing total hip replacement

Purpose: The Nottingham Extended Activities of Daily Living (EADL) scale is a popular outcome measure in stroke research. Its psychometric properties have not been tested in other conditions. Methods: EADL has been measured before, three and six months after hip arthroplasty. A sample was retested for reliability. Comparisons were made with the SF-36 and London Handicap Scale. Standard psychometric parameters were calculated. Results: The sub-scales and total score were approximately unidimensional on factor analysis and Cronbach's alpha, but did not form an adequate hierarchical (Guttmann) scale. Associations with other scales were in the expected direction and of approximately the expected strength, supporting concurrent and construct validity. Reliability was good. Responsiveness was poor compared with the other scales. Conclusions: The EADL is valid in patients with arthritis of the hip, and is reliable. However, it underestimates the size of health gain after hip arthroplasty compared with other scales.