The intra- and interrater reliability of the action research arm test: A practical test of upper extremity function in patients with stroke

Objectives: To determine the intra- and interrater reliability of the Actio n Research Arm (ARA) test, to assess its ability to detect a minimal clinic ally important difference (MCID) of 5.7 points, and to identify less reliab le test items, Design: Intrarater reliability of the sum scores and of individual items wa s assessed by comparing (1) the ratings of the laboratory measurements of 2 0 patients with the ratings of the same measurements recorded on videotape by the original rater, and (2) the repeated ratings of videotaped measureme nts by the same rater. Interrater reliability was assessed by comparing the ratings of the videotaped measurements of 2 raters. The resulting limits o f agreement were compared with the MCID. Patients: Stratified sample, based on the intake ARA score, of 20 chronic s troke patients (median age, 62yr; median time since stroke onset, 3.6yr; me an intake ARA score, 29.2). Main Outcome Measures: Spearman's rank-order correlation coefficient (Spear man's rho); intraclass correlation coefficient (ICC); mean difference and l imits of agreement, based on ARA sum scores; and weighted kappa, based on i ndividual items. Results: All intra- and interrater Spearman's rho and ICC values were highe r than .98. The mean difference between ratings was highest for the interra ter pair (.75; 95% confidence interval,.02-1.48), suggesting a small system atic difference between raters. Intrarater limits of agreement were -1.66 t o 2.26; interrater limits of agreement were -2.35 to 3.85. Median weighted kappas exceeded .92. Conclusion: The high intra- and interrater reliability of the ARA test was confirmed, as was its ability to detect a clinically relevant difference of 5.7 points.