Metaphors of Randomization & Clinical Trial Participation

What are these studies about?

Many clinical research studies need people to be put into different groups to compare results. This process, called randomization, can be confusing. To help explain it, doctors and nurses often use simple comparisons, known as metaphors. But some comparisons might make things more confusing. These studies looked at which comparisons help people understand randomization the best.

What did these studies find?

• Some people mistakenly think that they would be treated like a “guinea pig” if they joined a clinical research study and that joining a study should be a “last resort” when nothing else works.

• Common ways doctors and nurses explain how patients will be randomized in a research study are by saying it’s like a “flip of a coin” or “roll of the dice.” This is not an effective strategy because these terms create false associations between research and gambling.

• Participants suggested comparing randomization to the “sex of a baby.” This comparison emphasizes the commonality between randomization and pregnancy. When a women becomes pregnant, she can’t choose to have a male or female baby, but both result in a child. The same is true in randomized research studies. A patient (or their doctor) can’t choose which study group they can be in, but patients in both groups will receive the best possible care. The “sex of a baby” metaphor made people feel safer, more comfortable, and felt like they and a better understanding of what being randomized in a study meant.

• Using simple, positive ways of explaining research with examples that fit the community’s values helps people understand research studies and feel better about joining them.

• If people feel hopeful after hearing a comparison that they understand and makes them more comfortable, then they are more likely to want to join a study.

What is the bottom line?

Clear, respectful ways of explaining research with familiar examples helps people understand cancer research studies and can encourage more people join them. 

Krieger, J. L., Parrott, R. L., & Nussbaum, J. F. (2010). Metaphor Use and Health Literacy: A Pilot Study of Strategies to Explain Randomization in Cancer Clinical Trials. Journal of Health Communication, 16(1), 3–16.

Krieger, J. L. (2013). Last Resort or Roll of the Die? Exploring the Role of Metaphors in Cancer Clinical Trials Education Among Medically Underserved Populations. Journal of Health Communication, 19(10), 1161–1177.