September 19th, 2011

Decision-Making Shortcuts: The Good and the Bad

A patient comes to the ER complaining of 2 hours of substernal chest pain. An electrocardiogram reveals ST-segment elevation in 3 leads. A critical, ad hoc decision is made to call a “STEMI alert,” thereby activating the cath lab team and an interventional cardiologist. As the late Alvan Feinstein, the Yale educator and father of clinical epidemiology, once noted, “Every observant clinician has discovered that certain ‘short-cuts’ or other maneuvers, either of intellect or of action, can increase the efficiency of his work in clinical practice.”

These cognitive shortcuts are also known as heuristics. Understanding how we use them in medicine can help us improve practice. Because heuristics simplify difficult decisions, they help us avoid “analysis paralysis” under conditions of uncertainty that demand speed. In that way, they can improve decision-making effectiveness. But they can also lead to mistakes. Let’s start by exploring the good side.

The Benefits of Heuristics

Psychologist Gerd Gigerenzer uses an analogy, called a “gaze heuristic,” of a baseball player catching a fly ball. To do it successfully, a player simply fixes his gaze on the ball and starts running. If he maintains a constant angle of gaze by adjusting the direction and speed of his running, he will arrive at just the right spot to make the catch. By concentrating only on the angle of gaze, he can ignore the speed, trajectory, and spin of the ball, as well as the wind and many other factors. In effect, less is better. Gigerenzer has identified an “adaptive toolbox” of heuristics that we commonly use to address various types of problems. Here are a few:

The recognition heuristic enables us to use a single cue or a recognizable pattern of cues to quickly form a conclusion or size up a situation. Rapidly analyzing an ECG to diagnose a STEMI is one example. Seeing a pattern emerge from a patient’s historical narrative, leading to a diagnosis of chronic stable angina, is another.

The one-good-reason heuristic involves analyzing a short series of cues, then stopping when we perceive a strong or compelling cue. An initial ECG showing ST-segment elevation is, for example, a strong enough cue to prompt the immediate action of activating the cardiac cath lab. The trick is to start by first analyzing the high-impact cues.

The tallying heuristic allows us to organize cues in deciding among competing options. In the ER, I recently saw a patient with chest pain and a history of gastroesophageal reflux, which she had hoped was the cause of her pain. But she also had a history of bypass surgery and multiple cardiovascular risk factors. After weighing all the factors, we proceeded to the cath lab. She had two critical lesions and received two stents, and her pain resolved. Research shows that simply tallying up unweighted cues is quite effective. You just need to know which ones to consider.

Anchoring and adjusting, a heuristic I discussed in my previous blog post, describes how we assess subjective probabilities starting with an initial (anchor) impression and then adjust the probability estimate by incorporating new information such as a test result. Used properly, this heuristic can turn you into an intuitive Bayesian thinker.

Expert clinicians know how to filter out weak cues and focus on strong cues, as if separating signal from noise. Strong cues may be a key detail from a patient’s medical history, a bead of sweat on the brow of a patient complaining of chest pain, or certain ECG findings. Weak cues may be unreliable markers such as a soft carotid bruit or the lack of an S3 gallop.

The Risks of Heuristics

Like a medical procedure, heuristics can have both risks and benefits. Psychologists Daniel Kahneman and Amos Tversky studied many of the pitfalls of heuristics, such as these:

The base-rate neglect fallacy, explored in my previous post, surfaces when we misuse the anchoring and adjusting heuristic.

Representativeness involves jumping to an erroneous conclusion that is unlikely to be accurate, on the basis of an initial impression. ECG findings of ST-segment elevation due to early repolarization could lead to the erroneous diagnosis of acute MI in a young patient for whom that diagnosis is very unlikely. The medical adage “when you hear hoof beats, consider that it is a horse not a zebra” helps us avoid this trap.

Availability is a pitfall in which judgment is clouded by salient or recent events that happen to be more available and accessible to our working memory and intuition. Missing an uncommon diagnosis such as aortic dissection can be very troubling and memorable, but we should not then give this possible diagnosis undue weight in assessing subsequent patients.

By guarding against these tendencies, we can improve the chances that our heuristics — which, after all, are often useful — will yield good judgments.

How to Increase Awareness of Heuristics

Most physicians, whether trainees or seasoned clinicians, do not think consciously about heuristics. Becoming more aware of them and developing a common vocabulary will help us use them more effectively. There are two key domains where this kind of change could have a big impact.

Medical Training

Clinicians can be made more conscious of heuristics starting in medical school and continuing during fellowship training. Trainees may subconsciously learn about heuristics through experience, but that method is slow and unreliable. We should be able to teach these simple thinking processes overtly, just as we explicitly teach a one-hand tie to a surgical trainee. On my teaching rounds, I often include a brief discussion of how we use heuristics in medical practice. For example, I talk about anchoring and adjusting to teach the proper use of stress testing. I also discuss the recognition heuristic to illustrate the value of taking a detailed narrative history from a patient — patient-reported cues emerge as a recognizable pattern, like stars in a constellation. Including more explicit training on the use of heuristics would undoubtedly improve the consistency and quality of medical decision making.

Research into Medical Decision Making

Cognitive psychologists may discover other heuristics, but medical research is unlikely to invent new ones. After all, humans evolved to use heuristics long before modern medicine existed. Nonetheless, the cues that heuristics employ are domain-specific, with particular ones in each medical specialty and subspecialty. Analyzing the validity of those commonly used cues may be one way to advance research about decision making in the field of medicine. Addressing the basic science of medical decision making will require new ideas and true creativity.

What are your ideas for how to improve the use of heuristics in the practice of medicine?

7 Responses to “Decision-Making Shortcuts: The Good and the Bad”

  1. Louis Krut, MB.ChB. MD says:

    This becomes ridiculous. There is no formula for how to make the right decision. One just needs to know. Being told how a baseball player catches a fly ball will not make any of us eligible for inclusion in a national team; and using that example shows how little insight there is into making clinical decisions. We cannot look to psychologists for guidance. One is being encouraged to make a decision off the top of ones head. That is not good advice.
    The first thing to recognize is that we have a problem with no substitute for knowledge. Making a stab at it is certainly not the way to go.

    Competing interests pertaining specifically to this post, comment, or both:

  2. John E Brush, MD says:

    Dr. Krut,
    Thank you for your comments. But I think you may have missed my point. Where science provides the evidence, by all means, follow the rules. But many daily decisions are not specified by clinical trials or scientific principles. Most decisions, small and large, involving unique individual patients, are intuitive. Heuristics enable us to use our intuition rapidly through simplification. The point of the “gaze heuristic” analogy is that simplification can often vastly improve the process. The analogy uses an example from athletics to make a point about our thinking. And, by the way, I would argue that cognitive psychologists have a lot to teach us about how we think. That’s their area of expertise.

    I would ask: when was the last time you actually used Bayes Theorem to calculate a post-test probability? If you are like most physicians, you formally calculate the probabilities rarely, if at all. I bet that you intuitively calculate subjective probabilities using the anchoring and adjusting heuristic. So let’s recognize that and improve upon it, rather than creating the illusion of certainty, pretending that we don’t rely on heuristics and intuition.

  3. Karen Politis, MD says:

    Of course we use heuristics – in every move of our everyday lives, and also as physicians, because it’s the only way to work efficiently. The problems arise when external or internal factors, because we are human and prone to errors, lead us to the wrong decisions regarding our patients. How to avoid errors? I can think of two ways to start: 1. Be humble and always ready to question your judgment. 2. Work in a good supportive team which strives for excellence.
    Taking a detailed narrative history is a wonderful diagnostic tool and should be the sine qua non of our practice. Can anybody do this in a hectic ER? Can the patient even give us a detailed narrative history?

  4. Edgar Abovich, MD says:

    I wholeheartedly agree with Dr. Politis. Even though shortcuts can benefit some patients, for others it could be detrimental. Detailed history should still be the #1 tool in diagnosing a patient’s problem. If it is utilized routinely, a lot of unnecessary expensive tests, hospital admissions, and just simple mistakes could be avoided. However, for one reason or another, doctors are forced or unwilling to go through it and take shortcuts. In the hospitals it’s called “alert” or “protocol”, otherwise known as “one size fits all”. Each patient has a unique set of circumstances and usually should be approached as such.

    Competing interests pertaining specifically to this post, comment, or both:

  5. Anil Virmani, MD, DRM says:

    Protocols are important when you have different level of trainees or even well-trained professionals dealing with a recurrent problem. “Short-cuts” to decision making come only with experience and are usually reliable — only in rarest cases will experienced clinicians fail to arrive at the right diagnosis based on so called cues and short-cuts.Moreover, not only is every patient unique, but every physician also has his own unique approach to a clinical problem, which changes and further improves with experience.

    Competing interests pertaining specifically to this post, comment, or both:

  6. Carlos Eduardo Ramos Midence, Internal Medicine specialist, 3rd year cardiology fellow says:

    I remember in my felowship training telling the attending…something is wrong, I cannot quite catch it…He always said: Good, that is the first step, now go and read and clear your questions. I definitely agree heuristics exist within us, and in everyday practice. Reading abbout reinforces our decision-making process.

  7. Even in our era of indispensable imaging techniques and inexhaustible laboratory tests, a good anamnesis and a complete physical examination are essential in inducing heuristics and starting the diagnostic process. During my career I have much more often been right than wrong following this path. And I could also reject from the start unnecessary investigations .
    And I agree wholeheartedly that the students, besides being reminded that they should read constantly, should be teached to “feel” the patient- meaning, to amass as much information as possible about his work, his family, his culture.. It is time consuming, but it is the only way to practice a good medicine.

    Competing interests pertaining specifically to this post, comment, or both:
    No conflict of interest.