Grantee: Judy R. Rees

Judy R. Rees, BM, BCh, MPH, PhD

• Dartmouth College

Dr. Judy Rees is studying the impact of participants' beliefs and expectations about treatment assignment during a blinded, randomized controlled trial.

The randomized controlled trial (RCT) is often viewed as the gold standard of clinical research. It's certainly the best we have, but like any other study design it has potential flaws. If possible, the nature of the intervention is concealed from participants and investigators (blinding), to prevent bias in the experience, reporting or assessment of health outcomes, as well as in adherence to study protocols.

If we take the trouble to implement blinding in a RCT, we should understand the implications if blinding doesn't succeed, and that is one goal of Dr Rees's research. She will examine whether participants' expectations, preferences and beliefs about their assigned treatment influence health outcomes and adherence during a large RCT. And if participants' beliefs about the study treatment can generate bias, she will explore strategies to correct or prevent these biases in future trials.

It may not be easy to measure blinding effectiveness or to understand participants' beliefs about their assigned treatment. You can ask participants to guess which treatment they've been given during a trial, but what reply should we expect from someone who is truly blinded? Will they say they don't know, or will they hazard a guess? Should we elicit their beliefs after a completed study or look for changes in belief during the study? Even if a participant is successfully blinded, could they be biased by an incorrect belief about the treatment they are receiving?

In her recently funded study, Dr. Rees will try to answer some of these questions by examining the web of associations between beliefs, adherence and symptoms during a large randomized, chemoprevention trial.