Inter-rater reliability of the Barthel ADL Index: how does a researcher compare to a nurse?

OBJECTIVES: To investigate whether a nonclinical research assistant, using standardized scoring criteria, can reliably administer the Barthel Activities of Daily Living (ADL) Index in a sample of elderly inpatients. DESIGN: Paired comparison of nurse and nonclinical research assistant Barthel Index assessments. SETTING: Acute hospital wards from two hospitals in a UK Healthcare Trust, with a catchment population of approximately 224,000 people. METHODS: A consecutive sample of 94 elderly patients with a variety of medical problems. MAIN OUTCOME MEASURES: Barthel ADL Index, Folstein Mini-Mental Status Examination. RESULTS: Whilst the inter-rater reliability of the Barthel Index was within acceptable boundaries, two items out of ten had only fair agreement and low crude agreement (transfer and dressing) on Cohen's kappa scores. CONCLUSIONS: Depending on the differences observed in any particular context, the Barthel Index can be applied with reasonable reliability by nonclinical staff applying the standardized scoring criteria. It should be noted, however, that the kappa coefficients between clinical and nonclinical assessors tend to be lower than those found when comparing two clinically trained assessors in previous research.