OBJECTIVEThe purposes of this study were to establish the validity of a digital goniometer (DG) prototype, determine the inter- and intra-rater reliability of the DG as compared to the universal goniometer (UG), and evaluate and describe the clinical usability of the DG as a measurement tool.PARTICIPANTSEighteen healthy patient models and 5 physical therapists volunteered to participate.METHODSReliability testing of both the UG and DG was determined from the measurements of 5 therapists who performed 2 randomized, repeated measures of 5 joint motions on each of 6 patient models during 3 data collection sessions. To determine the validity of the DG, the investigators measured 8 randomly selected, computer-aided design (CAD) angles during each of the 3 data collection sessions. Physical therapist participants completed pre-/post-surveys to assess perceptions of clinical usability of the DG.RESULTSNo statistically significant differences were found between devices. Comparison of the DG and UG demonstrated no difference for intra- or inter-rater reliability, with the DG yielding higher inter-rater ICC values for each of the 5 motions measured.CONCLUSIONSThe DG has adequate concurrent criterion-related validity as a tool for assessment of joint ROM and equivalent inter- and intra-rater reliability to the UG. User surveys indicated that several of the novel features of the DG contributed to a higher likelihood that the device would be utilized by clinicians.