BACKGROUND: IQWiG, the German health technology assessment agency, is required to focus on patient-relevant endpoints as part of their cost-benefit analysis. Several patient preference studies conducted in Germany have identified “clear thinking” as a patient-relevant endpoint, but the measurement of this construct is limited by the absence of a conceptualization of clear thinking that is grounded in the patient experience. OBJECTIVES: To develop a conceptual model of clear thinking grounded in the experience of patients diagnosed with schizophrenia, aiding the creation of clear thinking scale. METHODS: A trained psychologist elicited definitions and examples of clear thinking from 25 German patients diagnosed with schizophrenia during open-end, semi-structured interviews. Theory building was aided by literature review, including a review of existing scales of cognition, and an additional 15 depth interviews with patients and clinicians. Data was analyzed using a grounded theory approach, leading to multi-dimensional conceptualization of clear thinking. RESULTS: Clear thinking can be conceptualized by four themes: a) staying organized (including daily activities, making decisions and having organized thoughts); b) making sense of the world (identifying reality, verbal comprehension and visual comprehension); c) feeling clear headed (confusion, slowness and pacing); and d) expressing thoughts and feelings (feelings, communication and fullness of life). CONCLUSIONS: This conceptual model provides researchers and clinicians with a framework to consider clear thinking as defined by patients diagnosed with schizophrenia. It will also provide the cornerstone for the development of a clear thinking scale to measure this patient-relevant endpoint and subsequently assess the validity of our conceptualization.