Research into patient aspects seeks to establish knowledge about the impacts of a health technology on patients, carers, and their families, which can be trusted by decision makers. To understand all the impacts of a health technology, research should be drawn from a range of disciplines and should encompass diverse perspectives, experiences, attitudes, preferences, values and expectations regarding health, illness, service delivery and health technologies. This may cover issues for the individual, social interactions, economic implications, ethical issues, and communication issues and be studied in both quantitative and qualitative research. The in-depth exploration possible in qualitative research arising from the fields of anthropology, sociology and psychology can elucidate complex patient aspects. Preferences research, which requires complex mixed methods, is now increasingly informing HTA recommendations. However, more needs to be done to build capacity to understand the rigour of this research and prove its legitimacy. This is essential for HTA practices that have historically focused on evidence grading systems based on evidence paradigms favouring randomised-controlled trials. All stakeholders have a role to play in generating and publishing high quality research into patient aspects and fairly assessing it so that it can be deemed sufficiently robust and widely used to inform decision making.