OBJECTIVE: To investigate the criterion-related validity, responsiveness, and clinically important differences of the ABILHAND questionnaire in patients with stroke. DESIGN: Validation and clinimetric study. SETTING: Three medical centers. PARTICIPANTS: Patients with stroke (N=51). INTERVENTIONS: A total of 51 patients with stroke received 1 of 3 upper extremity rehabilitation programs for 4 weeks. MAIN OUTCOME MEASURES: The ABILHAND and the criterion measures, including the Stroke Impact Scale (SIS), FIM, Nottingham Extended Activities of Daily Living (NEADL), and accelerometers, were administered at pretreatment and posttreatment. The score of the ABILHAND, given in logits, was based on the conversion of the ordinal score into a linear measure of ability. RESULTS: Correlation coefficients (Pearson r) were moderate to large between the ABILHAND and SIS physical domains (.54-.66), fair to moderate between the ABILHAND and FIM-motor and NEADL (.28-.48), and moderate between the ABILHAND and accelerometer data (.45-.54). The responsiveness of the ABILHAND was large (standardized response mean=1.27). The minimal clinically important difference range for the ABILHAND was .26 to .35, and 51.0% of the patients showed a positive change that exceeded the lower bound of a clinically important difference after intervention. CONCLUSIONS: The results support that the ABILHAND is an appropriate outcome measure for assessing upper extremity performance in daily activities in patients with stroke and is sensitive to detect change after rehabilitative interventions. The change score of a patient with stroke on the ABILHAND should reach .26 to .35 logits points to be regarded as a clinically important change. Copyright Copyright 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.