BACKGROUND: Regularly, patients are not involved in development of evaluative tools. Investigators define outcomes according to their interests. These can be different with those of the patients. Therefore, it may be difficult for patients to choose between treatment options, because the outcomes' measurements may not reflect their problems in daily life. Most ideally, patients are involved from the beginning in the development of an outcome measurement tool. In this study, a new concept was demonstrated in which a questionnaire was developed in collaboration with patients to evaluate the quality of surgical care of a frequently encountered entity (carpal tunnel syndrome) that is meaningful for and understandable by patients. METHODS: Through a patient participatory research in an academic hospital, 50 consecutive patients who recently underwent surgical decompression of carpal tunnel syndrome were asked to optimize a questionnaire. An existing questionnaire was sent to the patients with the request to grade the relevance of each question. They were also offered the possibility to add questions from their point of view. RESULTS: All questions were found relevant. Finally, the questionnaire was modified by adding one question proposed by the patients. They wanted to include a question that would evaluate the effect of the treatment. Therefore, a question was introduced to evaluate the effect of the surgery on the symptoms and signs with a six-item Likert scale varying from severely worsened to free of signs and symptoms. Finally, the EQ-5D-5 L was added as a measure of quality of life. CONCLUSIONS: The participation of patients is essential but until now not usual when a tool for evaluating the success of a treatment is developed. Information that is meaningful for patients but not obligate for researchers can easily be missed in the classical development of outcome measurement tools. This information will be crucial when future patients try to understand the findings of research in order to make an appropriate decision between eventual treatment options.