Patients with advanced-stage cancer often have a high symptom burden and reduced functional status, implying that the patients themselves should be involved in development and testing of interactive assessment tools. This paper reports on an assessment of use of a pain tool, which led to changes in both medium and program in order to adapt to the patients’ needs and abilities. Our study shows how a change in medium for pain assessment from paper via laptop to iPad affects the interaction with the tool on important aspects of use. We also show how changes of medium affect the readability of the output for health care workers. We achieved better results with an iPad-based pain assessment tool developed through user-centered design compared to both a paper-based and conventional laptop-based tool.