Objective: To examine the intra- and inter-rater reliability of the Action Research Arm Test (ARAT) at the item level after stroke.
Design: An intra-rater and inter-rater reliability study.
Subjects: Thirty-five participants (median age 62 years, median time post-stroke 22 months) with impaired upper extremity function after stroke were included in the study.
Methods: Two physiotherapists simultaneously, but independently, assessed the participants' performance in all 19 items of the ARAT twice in 1 day. A rank-based statistical method for paired ordinal data, including calculation of percentage agreement (PA), systematic disagreements (relative position (RP), relative concentration (RC)) and individual variability (relative rank variance (RV)) was used.
Results: Satisfactory intra-rater and inter-rater agreement was noted for all items except item 19, which was just below satisfactory level. Within and between raters, small but non-negligible systematic disagreements were found for items 11, 14 and 19 and for items 1, 4, 17 and 19, respectively. There was no disagreement due to random variance within or between raters.
Conclusion: The ARAT is a highly reliable observational rating scale at the item level after stroke. Awareness regarding the small systematic disagreements demonstrated in some items is, however, recommended when using ARAT.