Participant understanding is a key element of informed consent for enrollment in research. However, participants often do not understand the nature, risks, benefits, or design of the studies in which they take part. Research on medical practices, which studies standard interventions rather than new treatments, has the potential to be especially confusing to participants because it is embedded within usual clinical care. David Magnus discusses the ability of a range of multimedia informational aids to improve participant understanding in the context of research on medical practices. David Magnus, PhD is Thomas A. Raffin Professor of Medicine and Biomedical Ethics and Professor of Pediatrics and Medicine at Stanford University, where he is Director of the Stanford Center for Biomedical Ethics and co-Chair of the Ethics Committee for the Stanford Hospital. He is the former President of the Association of Bioethics Program Directors, and is the Editor in Chief of the American Journal of Bioethics.