Research seminar - Blinding in randomised controlled trials: To test or not to test?
3 August 2012
Presenter: Dr Ben Colagiuri
Dr Colagiuri completed his PhD in the School of Psychology, University of Sydney in 2009. Since then, he has worked as a postdoctoral fellow in the Centre for Complementary Medicine Research, University of Western Sydney and a Vice-Chancellor's Postdoctoral Fellow in the School of Psychology, University of New South Wales. He recently rejoined the University of Sydney as Lecturer in the School of Psychology. The majority of Dr Colagiuri's research focuses on the placebo effect, with a particular interest in placebo effects in clinical trials.
Participant blinding is an integral part of double-blind randomised placebo-controlled trials. When successful, it indicates that any differences between treatment groups are unlikely to result from participant expectancies. There is, however, increasing evidence suggesting that blinding often fails. This has led some researchers to question the validity of testing for blinding, given that it is difficult to separate guesses about treatment allocation from actual treatment responses. Notably, in light of these concerns the latest CONSORT statement removed a previous item suggesting that trialists should report the results of tests of blinding. In this talk, I will present experimental evidence indicating a bi-directional relationship between guesses about treatment allocation and treatment responses, which suggests that participants do base their guesses about treatment allocation on whether or not they observe improvement, but that these guesses about treatment allocation can also affect their treatment response via the placebo effect. On this basis, I will argue that testing for blinding does provide important information about the possibility of bias in a trial and that trialists should discuss the success or failure of blinding when reporting the results of a trial.
Light refreshments served afterwards.
Hosted by the NHMRC Clinical Trials Centre
Time: 3.30pm - 4.30pm
Location: Level 5 Training Room, Medical Foundation Building