Background and Purpose-Evaluating the impact of new treatments requires the use of reliable, valid, and responsive outcome measures. However, given the wide range of instruments currently available, it is not always straightforward for healthcare professionals to select the most appropriate tool. In this review, we propose a potential approach to scale selection. Methods-In designing a new study of the impact of a robotic device in stroke rehabilitation, we developed a three-stage scale selection strategy. First, two guidance documents (Medical Outcome Trust and Food and Drug Administration PRO Guidance) were reviewed to identify key scale assessment criteria. Second, consideration was given at a theoretical level of the concepts and domains relevant to the goals our study. Third, a comprehensive literature search strategy and review were developed in conjunction with healthcare professionals and psychometricians. Identified scales were appraised regarding their psychometric properties and clinical content. Results-Forty-five measures were initially identified and appraised. From a clinical content perspective, none of the measures were considered to be sufficient on their own to capture all the important outcome domains in this study. However, 3 measures were identified that best met our review criteria: Stroke Key Words: cerebrovascular disorders Ⅲ outcomes Ⅲ rehabilitation Ⅲ scales Ⅲ upper extremity S troke is currently the single largest cause of adult disability in the United Kingdom with one third of people who have had a stroke left with long-term disability. 1 New therapies such as repetitive practice through the use of robotics 2 have the potential to enhance the recovery of neurological function post-stroke. 3 The evaluation of such treatments increasingly depends on the use of valid, reliable, and responsive outcome measures. 4,5 Therefore, selecting the right measure for the right study is essential and rests on a clear understanding of the scientific quality of the rating scales. 6 Systemic reviews can help to select outcome measures. For example, Ashford et al 7 reviewed measures for the hemiparetic upper limb, identified 6 scales that met their selection criteria, but concluded that currently there was no single reliable and valid measure available to capture the full range of functional tasks in the hemiparetic upper limb. This type of systematic review provides invaluable information but also raises important questions. For example, how well targeted are different measures to the goals of specific interventions? How do we select the best available measures for future clinical studies? What criteria should be used and why?The aim of this article is to present a scale selection strategy for evidence-based scale selection in stroke research. We describe three steps. First, we reviewed two recent psychometric guidance documents that define key scale assessment criteria. Second, we considered, at a theoretical level, clinical issues, concepts, and domains important to include in stroke outcome resear...