The effect of item observability, clarity and wording on patient/nurse ratings when using the ASA scale

Many studies show discrepancies between patients' and professionals' rating s on the same questionnaire regarding the patient's health. A relevant ques tion is whether the differences in ratings reflect real differences between patients and professionals or whether they are caused by characteristics o f the instrument. In this study, we address the latter option by examining the effects of 3 item characteristics (item wording, observability and clar ity) on the degree of patient/nurse discrepancies in ratings of the items o f the Appraisal of Self-care Agency (ASA) scale. Secondary analysis on 252 patient/nurse ratings showed that item wording (positively and negatively f ormulated items), and the observability of the items have a significant eff ect on the mean absolute difference score. No effect was found for clarity. These results were generally confirmed by subgroup analyses.