How do you think? Have you ever stopped to consider it? Often the errors we make at work are a result of cognitive reflexes we could unlearn if we examine the way we process information.

Dr Michael Shanahan, rheumatologist and occupational and environmental physician, spoke at the People at work – managing complexities conference and explained that many of the common errors made by medical practitioners when diagnosing patients come down to cognitive factors.

A 2005 study conducted by Mark Graber and others looked at 100 autopsies where there was considered to be a diagnostic error in the process of death. The study found that 10 per cent of the errors could have no fault attributed to them (perhaps the patient had withheld information or lied about their health); 65 per cent of deaths were found to be due to system related causes; and 74 per cent (in what was an overlapping study) found that cognitive factors contributed significantly.

Cognitive factors, Dr Shanahan explained, include faulty knowledge, faulty data gathering, poor etiquette, and thinking and processing – the most important factor.

Dr Shanahan drew attention to an article by Dr Pat Croskerry, ‘The importance of Cognitive Errors in diagnosis and strategies to minimise them' (see link below), which looked at cognitive processing errors that potentially anyone can make.

Dr Croskerry's study shows that one of the important errors that can be made in diagnosis is “framing” – how people are influenced by the way information is presented to them. For medical practitioners this can occur in the referral letter or the workers' compensation letter. Immediately a context has been set for the medical practitioner who is being asked to respond in line with the information being presented to them.

Dr Shanahan outlined other common errors from the study. An anchoring error is the tendency to run with first impressions, arriving at a diagnosis too early, which makes it difficult to absorb other information later that may contradict the original diagnosis.

Other errors include:

• Accepting a diagnosis before it's fully verified
• Blind obedience – unquestioningly believing to be correct any authority or technology and not thinking critically
• A disposition to judge thing as being more likely if they readily come to mind. eg A medical practitioner who's seen ten patients with the same condition might jump straight to the same diagnosis when an eleventh patient displays similar symptoms
• Looking for evidence to support a diagnosis rather than to refute it
• Opting for diagnostic decisions that will lead to good outcomes
• Failing to act sooner
• Misidentifying a sign or symptom
• Being distracted by other issues.

What might seem a long list of common errors is not, however, without remedies. To minimise the chances of one of these errors occurring, Dr Shanahan outlined the importance of medical practitioners learning about ‘cognitive debiasing strategies' – ways to teach ourselves not to follow reflexes in the thought process that can lead to inaccurate diagnoses and more objectively consider our decisions.

There is also specific training that works on identifying flaws and biases in thinking and providing directed education to overcome them.

Dr Shanahan reiterated some tips from Dr Croskerry's article: reconsider diagnoses in light of new data or second opinions, consider cases examined from an alternative perspective and be critical about authority that is remote from you.

Dr Shanahan suggested the following strategies as starting points to minimise diagnostic error:

• Allow adequate time for data gathering and ask open ended questions
• Develop a reflective approach to diagnostic processing and thinking
• Always ask yourself ‘What else could this be?'
• Regularly revisit diagnoses with the benefit of time
• Interpret investigations with a working knowledge of their strengths and limitations
• Use decision making support tools when available
• Learn from your errors

There is potential for error in any field, in any position. Examining the way we think and arrive at decisions is the best way to discover how we make errors, and how we can teach ourselves not to continue making the same ones.


The importance of Cognitive Errors in diagnosis and strategies to minimise them, Academic Medicine, Vol.78, No.8/August 2003