Decision-making capacity is the gatekeeping element for a patient’s right to self-determination with regard to medical decisions. A DMC evaluation is not only conducted on descriptive grounds but is an inherently normative task including ethical reasoning. Therefore, it is dependent to a considerable extent on the values held by the clinicians involved in the DMC evaluation. Dealing with the question of how to reasonably support clinicians in arriving at a DMC judgment, a new tool is presented that fundamentally differs from (...) existing ones: the U-Doc. By putting greater emphasis on the judgmental process rather than on the measurement of mental abilities, the clinician as a decision-maker is brought into focus, rendering the tool more of an evaluation guide than a test instrument. In a qualitative study, the perceived benefits of and difficulties with the tool have been explored. The findings show on the one hand that the evaluation aid provides basic orientation, supports a holistic perspective on the patient, sensitizes for ethical considerations and personal biases, and helps to think through the decision, to argue, and to justify one’s judgment. On the other hand, the room for interpretation due to absent operationalisations, related ambiguities, and the confrontation with one’s own subjectivity may be experienced as unsettling. (shrink)