PURPOSE: Circumduction of the wrist consists of a circular motion combining flexion, extension, and radioulnar deviation without simultaneous supination or pronation of the forearm. This pattern of flexion-extension and radial-ulnar deviation coupling is vital in common tasks; however, its evaluation in hand clinics is limited by the availability and ease of current tools. We present the construct, criterion, test-retest, and inter-rater validity of a new circumduction measurement device. METHODS: Splint volunteers (n = 42) and hand clinic patients (n = 51) were studied to assess different aspects of validity and reliability for the circumduction jig. Known-group validation was used to assess construct validity and demonstrate the ability of the device to differentiate between patients with lesser or greater circumduction values. Criterion validity was demonstrated by comparing the circumduction measures of the device to flexion, extension, ulnar deviation, and radial deviation. Test-retest reliability was established by comparing the results of repeated circumduction measures for the hand clinic patients by 2 blinded, independent researchers, and inter-rater reliability was determined by evaluating the correlation in circumduction measures taken on the same patient by different blinded, independent researchers. RESULTS: Circumduction measurements significantly decreased (test for trend, p textless .01) across the 3 different treatments that represented progressively reduced range of motion, establishing construct validity of the device. Flexion, extension, and radioulnar deviation all correlated significantly with circumduction; the correlation values ranged from 0.46 to 0.82 (p textless .01) among all subjects (93 subjects, 228 measurements). Intra-rater reliability was 0.98 (p textless .01) for both evaluators, and inter-rater reliability was 0.94 (p textless .01). CONCLUSIONS: The present validation study demonstrated criterion, construct, test- retest, and inter-rater reliability for a newly designed circumduction measurement device.