Background: Measuring or evaluating outcomes is a common activity for many speech-language therapists (SLTs). A major focus has been on external forces claiming outcome evaluation to optimize quality and the use of resources without integrating the viewpoints of SLTs. Aims: To identify the purpose of outcome evaluation by letting SLTs identify not only the actual demands for outcome evaluation, but also the role of outcome evaluation in aphasia therapy in the clinic. Methods & Procedures: Twelve SLTs participated in semi-structured interviews to identify the demands they met for outcome evaluation as well as the role the outcome evaluation had in their work with people with aphasia. The interviews were transcribed verbatim and analysed by means of qualitative thematic analysis. Outcomes & Results: Six themes corresponding with the aims of this study were identified. These show that the SLTs initially evaluated outcomes because of external demands and interests. However, they also describe the process as a necessary activity inherent to therapy and state that they would not want to be without it. The outcome evaluation is seen as an interactive process between SLTs, clients and possibly significant others. Not only it is seen as a product in which outcome and/or client satisfaction is documented, but also it is described as a dynamic process that benefits the clients, significant others, the therapy and the SLTs themselves in various ways. This role of outcome evaluation ranges from enhancement of insight and promotion of acceptance for the clients and significant others to planning the next step in therapy or in life with aphasia after therapy. In all of which the clients play a significant role, since their active participation is sought throughout the sessions. Conclusion & Implications: The results suggest an interesting relationship between treatment policy and treatment practice, where an initial administrative initiative to conduct outcome evaluation is adopted by the SLTs and made into a meaningful part of therapy in which the clients play a significant role.