Issues in the conceptualization and measurement of participation: an overview.

While participation is increasingly defined as the key outcome of rehabilitation, disagreements on and shortcomings in the definition, operationalization, and measurement of this concept abound and interfere with the progress of clinical services and research. This article explores a number of the major issues related to the quantification of participation and makes suggestions for new directions, using the following orienting questions: What is the definition of participation? Where is the border between Participation and Activity? Is there more to participation than performance? What domains should be included in a participation measure? What are the appropriate metrics in quantifying participation? How do we define adequate participation? How should participation be operationalized? What is the proper measurement model for participation instruments? How should we collect data on participation? How do we evaluate the quality of a participation instrument?