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01/23/95

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Common psychological pitfall can skew complex medical decisions

STANFORD -- Like the rest of us, family doctors, brain surgeons and legislators are subject to a bias toward the status quo when given too many choices, says a new study reported in the Jan. 25 issue of the Journal of the American Medical Association.

In today's medical setting, doctors commonly face complex decisions with multiple choices, said Dr. Donald Redelmeier, a Fulbright scholar in Stanford's Psychology Department and a professor of medicine at the University of Toronto. "For example, there are 13 medicines available for treating Parkinson's disease, 31 for chronic bronchitis and 91 for hypertension."

His study with psychologist Eldar Shafir of Princeton "shows that the same cognitive bias that has been observed in college students facing complex decisions can also be found in family physicians, expert brain doctors and health policy makers," Redelmeir said.

The bias is that in complex situations people will choose an option they would have declined if fewer options were available. "In particular, the status quo option paradoxically becomes more attractive," he said.

Stanford psychology Professor Amos Tversky, with whom Redelmeier is working this year, was involved in earlier research that pinpointed the nature of bias, but it is well known intuitively to advertisers, real estate agents, fast food marketers and others who watch consumer behavior, Redelmeier said.

"Real estate agents know if they want to make a sale, they shouldn't show you too many different houses. McDonald¹s knows its total sales may decrease if it offers a larger menu, and intuitively, the advertising industry likes to position its product as the one-and-only painkiller you can take once a day or the one-and-only automobile with two air bags," he said.

Because of the growing complexity of health care, Redelmeier said he and Shafir wanted to demonstrate that cognitive biases apply also to medicine. Highly educated doctors, he said, need to realize the same judgment errors made by college students also may appear in their decisions in complex situations. "It is one of the more general aspects of human personality, and medical training does very little to call attention to it. Research in non-medical areas suggests that there are steps people can take to reduce these pitfalls in judgment.

"One of my largest motivations for the research is my belief that people's ability to make sound decisions is one of the most important elements of health care. If those making decisions realize they are subject to this bias and take corrective steps, patients may experience fewer errors, better treatment and reduced costs."

In their research, Redelmeier and Shafir sent surveys containing medical scenarios to three groups - family doctors in the Ontario College of Family Physicians, neurologists and neurosurgeons in the North American Symptomatic Carotid Endarterectomy Trial and elected politicians in the Ontario Provincial Parliament.

The scenario presented to family physicians involved deciding whether to start a new medication for a patient with chronic right hip pain. The neurologists and neurosurgeons were presented with a situation in which the doctor needed to prioritize the patients awaiting carotid artery surgery because of a temporary limitation on operating room availability. The scenario sent to legislators discussed health care expenditures and asked them to decide whether to close a hospital.

Half of each group was given a scenario involving a choice between only two alternatives. The other half was given a third alternative. The family physicians, for instance, were asked to decide whether to start the patient on a new medication. For half the physicians, chosen at random, only one medication was available. For the other half, two similar medications were available.

In all three groups of participants, those presented with the more complex scenario were more likely to resort to the distinct option or the status quo choice than were those facing the simpler scenario.

For example, family physicians were less likely to prescribe a medication when choosing between two medications than when deciding about just one (53 percent prescribed medicine in the more complex scenario compared to 72 percent in the simpler scenario).

The legislators presented with a second hospital to consider closing were more likely to stay with the status quo and close neither hospital.

The legislators' scenario may point to one reason why health care reform failed last year in Congress, Redelmeier said. "One of the characteristics of the discussion was multiple competing proposals. In that scenario, the status quo looms large."

There are steps people can take to reduce the effect of these cognitive illusions or pitfalls in making judgments, Redelmeier said. For example, after a doctor has made his or her first choice selection, he or she can "double-check the work by identifying the second choice," he said, "and verifying that the first choice is indeed more attractive than the second choice."

In their journal article, Redelmeier and Shafir say that the psychological factors are "often mild and by no means rampant in medical decisions. Some situations are straightforward and do not tap a physician's uncertainties or limitations. Physicians also tend to work in collegial settings and therefore may be guided by colleagues, patients and the medical literature prior to making a choice.

"The present study suggests, however, that people do not always resolve medical decisions by analyzing benefits and harms in a reliable manner. Instead, people may resort to intuitive judgments that render them prone to cognitive biases. Psychological theory predicts that these cognitive biases will appear when people have difficulty deciding between conflicting alternatives, face situations of substantial uncertainty or consider outcomes that have long-term consequences."

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