Study shows clinicians’ expectations of the benefits and harms of treatments and tests are often inaccurate

January 10, 2017

Health professionals rarely correctly estimated the benefits and harms of medical treatments and tests - accurate for only 11 per cent of the benefits and 13 per cent of the harms examined - potentially contributing to an increasing level of intervention overuse, a new study by Bond University has found.

The research, published today (Tuesday, January 10) in one of the world's most influential medical journals, JAMA Internal Medicine, is believed to be the first systematic review of clinicians’ expectations of the benefits and harms of medical interventions.

It found clinicians more often underestimated, rather than overestimated, the harms - and overestimated, rather than underestimated, the benefits - of interventions.

The study, conducted by Professor Tammy Hoffmann and Professor Chris Del Mar from Bond University's Centre for Research in Evidence-Based Practice (CREBP), reviewed 48 studies involving a total of 13,011 clinicians, mostly doctors, that examined expectations of treatments, medical imaging, and diagnostic and screening tests.

Professor Hoffmann said the inaccuracies occurred across a wide range of treatments, tests and screening tests.

“We know from our earlier research that patients also have inaccurate expectations, and most people think that interventions will help more and harm less than they actually do," she said.

"The reality is, if both clinicians and patients are bringing inaccurate expectations into the consultation, the potential for misguided, ill-informed decisions is very high.

“Both patients and clinicians need ready access to high-quality, unbiased, easy-to-understand information about the benefits and harms of treatments and tests to see this improve in the future."

Professor Chris Del Mar said keeping up-to-date with the latest research was difficult for many clinicians.

“The amount of new research being published every day is staggering and keeping abreast of it all and working out what is quality research and what is not is a challenge,” he said.

“It is very important we find ways of helping to get accurate and up-to-date information about interventions’ benefits and harms into the conversations that clinicians and patients have." 

Please note; the study abstract is available at:

Hoffmann TC, Del Mar CB. Clinicians’ expectations of the benefits and harms of treatments, screening, and tests: a systematic review. JAMA Int Med. doi:10.1001/jamainternmed.2016.8254