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The Anchoring Heuristic and the Triple Aim
The triple aim[1]—improving the patient experience, improving the health of populations, and reducing the cost per capita—has been proposed as the solution to our current medical care dilemma. The notion is that to be effective, a health care system needs to address all three goals simultaneously. Not explicitly stated is the notion that consistent application of evidence-based medicine and continuous improvement methods are one of the key tools. I have previously suggested that the problem of patient activation is the Achilles’ heel of health care reform. But it is not just patient behaviors that will obstruct attaining the goal. Physician behaviors also matter. The practice of medicine involves a constant series of comparisons—what the patient says is compared to similar conversations in the past. It also involves the rapid serial formulation and rejection of diagnostic considerations that occur to the physician doing the assessment. This is inherently subjective because the conversation invariably involves communication between two or more people. We really should be surprised the diagnostic process works as well as it does rather than be disappointed when it does not. I think the people proposing health care reform routinely underestimate two predictable psychological biases, perhaps because they are difficult to measure. The first is a belief in the effectiveness of medical interventions. Young physicians have invested enormous time, energy, and effort mastering the craft of medicine, and (unconsciously) believe the goal is the get the right therapy to the patient. With age and experience, the physician, again unconsciously, may come to the recognition the goal is to get the right patient to the therapy. When I was a medical student, the chief of general surgery was an elderly man of many years’ experience in the practice and teaching of surgery. He rarely operated, though. He often said almost any competent surgeon could do an operation. What he could do better than most was decide which patient should have an operation and which should not. Patients sometimes recognize this human tendency and ask for a second opinion more often when the physician is young than when he or she is older. I remember a pediatric urologist who commented that when he first went into practice he could look at the X-rays and know what procedure the child needed. He would then talk to the mother, who would look at him and ask for a second opinion. Now that he was the one with the gray hair, everything was the same except he was almost never asked to arrange a second opinion. The other major bias is the impact of a bad result. In decision analysis, the anchoring heuristic is the term applied to the tendency to overrate the first piece of information presented in a decision.[2] In medical decision making it can be used to denote the tendency of a bad experience to trump all the normal experiences. Some years ago, I was presenting a patient for Grand Rounds at a nearby medical school. The patient was a 19 year old male sent to me by a local physician because of severe hypertension that did not respond to two drugs from the sample drawer. I used this case as a springboard to discuss Bayesian analysis of when to screen for secondary hypertension.[3] After going through this analysis, I showed a photograph of a skin lesion the patient had, which had been previously diagnosed as a neurofibroma. I then pointed out this increased the prior probability the patient had a pheochromocytoma, a very rare cause of secondary hypertension, so I ordered diagnostic tests. We found he had a 20 cm tumor. Unfortunately, despite resection, the disease recurred, proving it was a malignant pheochromocytoma and he died of metastatic disease about six years after he was first diagnosed. During the question and answer period following the presentation one of the professors got up and said he once had had a young man who underwent an arteriogram looking for renal artery stenosis, another secondary cause of hypertension, and had an unrecognized pheochromocytoma. He had a catastrophic rise in blood pressure and died. The professor decided that henceforth all patients undergoing arteriography needed to have tests done to make sure they did NOT have a pheochromocytoma. He was oblivious to the fact that he had never had a second case, and did care how much expense his bad experience had added to the care of every subsequent patient. This is an extreme example, but all physicians find they can access their bad experiences more clearly than their average experiences, and this induces bias in the way patients are managed. Physicians have standard diagnostic approaches they apply to patients, but there are always other tests which are not commonly ordered. Let the physician have a bad result, though, and the frequency with which the rarer tests are ordered will go up, at least until the physician gets his/her confidence back. If he or she is named in a malpractice suit, the likelihood of a dramatic increase in testing goes up. This phenomenon has been labeled “defensive medicine.” While lawsuits get the lion’s share of the blame for this, the phenomenon would occur even if there were no lawsuits. “Choosing Wisely”[4] is an effort spearheaded by the American Board of Internal Medicine Foundation to get physicians and patients to consider tests and procedures of “low value” that should not be done. In an extended discussion of the initiative, Morden and associates[5] noted “the message, the messenger, and the method are key features of this stewardship initiative. The creators of the Choosing Wisely campaign have carefully crafted a recommendation for ‘conversation’ emphasizing individual patients’ needs as the top priority, preserving the preeminence of physician judgment, patient choice, and the therapeutic dyad.” While the program has received wide support, backlash has appeared. The Advisory Board, for instance, citing an article in Modern Healthcare, quoted a physician saying “We have to be careful when we label something as being unnecessary that we make sure the general public realizes that just because something has a low yield doesn't necessarily mean that it's unnecessary.”[6] In other words, the program is encountering the problem of the bad result making low yield tests and procedures seem more valuable than they really are—just like the professor in the earlier illustration. I have emphasized these psychological realities because I often hear business people and policy makers talk about health care as if these realities were just aberrations that represent noise of no consequence. This view fails to recognize the fundamentally experiential nature of medical practice. Rather than noise, these psychological realities reflect the fundamental uncertainties involved. If we accept that the “signal” is inherently fuzzy, we may be able to build systems that operate within predictable limits. If we insist on seeing these psychological issues as noise, we will continue in what I predict will be fruitless search for precision. 30 April 2015 [1] http://www.ihi.org/engage/initiatives/TripleAim/Pages/default.aspx. Accessed 29 April 2015. [2] http://en.wikipedia.org/wiki/Anchoring. Accessed 29 April 2015. [3] Given the usual data about the sensitivity and specificity of the various diagnostic tests, they are not helpful unless there is a least a 10% chance the patient has the disease in question. [4] http://www.choosingwisely.org/. Accessed 29 April 2015. [5] Morden NE, Colla CH, Sequist TD, Rosenthal MB. Choosing Wisely—The Politics and Economics of Labeling Low Value Services. N Engl J Med 2014;370(7):589-592. doi: 10.1056NEJMp1314965. Accessed at http://www.nejm.org/doi/pdf/10.1056/NEJMp1314965 29 April 2015. [6] http://www.advisory.com/Daily-Briefing/2013/08/27/Is-the-Choosing-Wisely-campaign-wise-Experts-weigh-in. Accessed 29 April 2015. |
Further Reading
How did you know? How do experts know? The roles of formal and tacit knowledge are considered. Knowledge Management Knowledge management (KM) covers any intentional and systematic process or practice of acquiring, capturing, sharing, and using productive knowledge, wherever it resides, to enhance learning and performance in organizations. Which strategy for knowledge management is appropriate in dialysis clinics? The Problem of Scale Have we lost our moral compass as medical organizations have grown larger? Time Span Preferences |