Review of Research on Conveying Risk Information Presented During the Informed Consent Process
Dr. Rector is part of the HSR&D Center for Chronic Disease Outcomes Research in Minneapolis.
A significant concern in research ethics is whether prospective research participants are given adequate information about the potential risks of research participation during the informed consent process. Moreover, words commonly used in the process may be ambiguous. Words such as “rarely” and “possible” are used to describe the possibility that participants might experience adverse effects during the study intervention; however these words are open to interpretation. One study indicated that patients thought “rare” deaths would be significantly less likely than “rare” pneumonia following surgery. Other studies raise concerns about people’s ability to comprehend numbers. For example, a survey of older female veterans showed that nearly half could not convert 1% to 10 in 1000. The author reviews several studies to assess whether or not informed consent language adequately communicates risk to participants.
- Whether numeric or word formats lead to better decisions about participation in research is largely unknown. A few small studies indicate that using numbers rather than words to communicate the likelihood of adverse outcomes can make a difference, and suggest that many people prefer the chances of adverse effects be expressed in numerical terms.
- The author recommends minimizing probabilistic words (e.g., “rarely,” “possible”) and encourages the use of simple frequencies with common denominators (e.g., “one out of 100 people”).
- The findings from this review are insufficient to formulate guidance but confirm the need for additional research on conveying risk information to study participants during the informed consent process.
Rector, T. How Should We Communicate the Likelihood of Risks to Inform Decisions about Consent? IRB: Ethics & Human Research July-August 2008;30(4):15-18.