This chapter introduces basic concepts related to the development of outcome measures, and demonstrates their applications in stroke rehabilitation. Measures used to evaluate the outcomes of rehabilitation for individuals with stroke generally reflect physical, psychologic, or social characteristics of people. Other constructs one might want to assess include impairment, ability/disability, community mobility, health status, self-efficacy, fitness, participation or quality of life. Such constructs are evaluated using standardized scales. The evaluation of walking competency after stroke is used as an example to illustrate the selection of appropriate outcome measures for this population as well as their relation to participation. The chapter illustrates how laboratory outcome measures can be used to validate clinical measures, explain the results of clinical outcomes, develop new measures, and guide therapy. With the rapid development of neuroimaging techniques, it has become possible to study neural organization associated with motor recovery after brain damage.