From G. Gigerenzer, Risk Savvy. Penguin (Draft, cite only with permission from the author)

6 Defensive Decision Making

Unfortunately we don’t get sued for doing
C-sections. We get sued for not doing
C-sections soon enough. That has really
increased, I think, our C-section rate.

From Richard Waldman, 2010, president of the American College of
Obstetrics and Gynecologists

Many a committee meeting ends with “We need more data.” Everybody nods, breathing a sigh of relief, happy that the decision was deferred. A week or so later, when the data are in, the group is no further ahead. Everyone’s time is wasted on another meeting, on waiting for even more data, and on the lack of courage to make a decision. Not making a decision or procrastinating in order to avoid responsibility is the purest form of defensive decision making. If something goes wrong, somebody else made the decision. But there are more subtle and intelligent ways. Fear of litigation and accountability has developed defensive decision making into an art. It’s the modern art of self-defense at the cost of the company, the taxpayer, or the patient.

Hire the Second-Best

A friend of mine worked for an international charitable corporation that does much good. Doctors and nurse volunteers provide urgent medical care all over the world to victims of disaster and war. To respond at a moment’s notice to urgent emergencies, the organization must assess a crisis quickly and make decisions on people’s needs, independent of political interests. Like many charity organizations that are financially independent, the organization lives from donations. Donors want to be sure that their money is spent as intended and not wasted. To reassure them, the organization hires accounting firms to check and certify its work.

What accounting firm to choose? In one instance, the choice was between a small local firm that asked a reasonable price and was most knowledgeable and a large international firm that charged more money and had less knowledge but a big name, such as Ernst & Young or KPMG. The local firm would send experienced specialists while the large firm would send young fellows who knew comparatively little. The best decision seems obvious: Hire the local company and you get the better expertise for the better price. Yet that did not happen. The corporation chose the second-best option, the big name. Why? A non-profit organization is accountable to its donors. Imagine something going wrong, as it is always bound to do. If donors learn that a firm they’ve never heard of had checked the books, alarm bells would go off. But if they had heard of the accounting firm, fewer questions would be asked. This story illustrates a perplexing process:

Defensive decision making: A person or group ranks option A as the best, but chooses an inferior option B to protect itself in case something goes wrong.

Choosing a second-best option is not stupidity or bad intention. Defensive decisions are imposed by the psychology of the system. In the present case, the psychology was based on a rule of thumb:

Recognition heuristic: If one company’s name is recognized but not the other, infer that the recognized company provides the better value.

This simple rule is often a good guide.[1] But it can lead to the dominance of a few firms that grow bigger and bigger and can no longer deliver the best quality. Defensive decision making draws on brand name recognition, but also on anything else that protects the decision maker. The result is a paradoxical social game: The corporation protects itself against their donors, wasting part of the donations on inferior services for fear that the donors might cause trouble if they didn’t.

This game of self-defense is played not only in non-profit organizations.

Hide Your Intuition and Hurt Your Company

Having a gut feeling means that one feels what one should do, without being able to explain why. We know more than we can tell (see Chapter 11). A gut feeling, also called intuition, is neither caprice nor a sixth sense, nor is it clairvoyance or God’s voice. It is a form of unconscious intelligence. To assume that intelligence is necessarily conscious and deliberate is a big error. Most parts of our brain are unconscious, and we would be doomed without the vast experience stored there. Intuition is indispensable in face of uncertainty, while for known risks calculated intelligence may do the job. In my experience, about half of professional decisions in large companies are gut decisions. But if a manager publicly admitted, “I had a hunch,” that might not go over well. In our society, intuition has become suspicious. For that reason, managers typically hide their intuitions, or have even stopped listening to them. I have observed two ways to conceal or avoid gut decisions.

1. Produce reasons after the fact.

An executive has a gut feeling about an alternative to pursue but fears admitting that it is what it is. So she asks a trusted employee to spend two weeks on finding reasons after the fact. With this list in hand, the executive presents the gut decision as if she’d arrived at it by considering all these factors. Rationalization after the fact costs a company time, money, and resources. Another version is to hire a consulting firm. It will deliver a 200-page document analyzing reasons for the gut decision – of course without mentioning that there was ever such a thing in the first place. This procedure costs even more money, time, and attention. Both tactics are ultimately motivated by the leader’s fear to take on responsibility – which is what a gut decision is all about.

2. Defensive decision making.

Here, the strategy is to abandon the best option because it cannot be justified if something goes wrong and to favor a second- or third-best option. For example, a senior manager once had a gut feeling to enter a foreign market with a new product but, unable to explain why, went along with the others and voted against the opportunity. Again, the idea is to protect oneself, this time by choosing second-best solutions for the company. This procedure probably costs a firm more than the strategy of looking for reasons after the fact because of the consequences of second-best courses of action.

How frequent is defensive decision making? To find out, I have interviewed managers, senior managers and CEOs in large companies. One of these was a leading international technology services provider with annual revenues of around fifty billion dollars. The company had problems with slow decision making, both inside the firm and when dealing with their customers. With the help of a top executive who had the trust of the senior managers, we asked 36 of its executives how often they chose a second-best option in order to protect themselves, instead of choosing what they believed was the best option.  We made sure that the executives were from all levels of the hierarchy, including managers, heads of departments, group executives in charge of a branch of the company, and members of the executive board. Thirty-two answered without having to be asked twice, which signals how important they found the issue. Specifically, the managers were asked: “Consider the last ten important professional decisions in which you participated. How many had a defensive component?”

Seven out of 32 managers said they never made a defensive decision (Figure 6-1). One of them, a male executive in his 50s, explained: “I believe I have always decided in the best interest of the company. I do well only if the company is doing well. It’s my passionate conviction. Even if this company gave me the pink slip, I would still do the same for the next company.” That is the type of manager everyone wants to have. But these ideal managers were a minority.

A dozen managers admitted a few defensive decisions, between one and three. One said that these were motivated by fear of blame and of compromising himself by being responsible for an error, which might lead to loss of peer esteem. Others invoked situations with lack of time and incalculable risks. An executive in his early 60s openly admitted that in a few cases he’d simply lacked the courage.

Nearly a third of the managers, however, revealed that about half of their decisions were defensive. One justified his behavior in this way: “I want to be part of the majority, to protect myself from personal attacks. Perhaps I fear my own courage.” Another complained that the company provided no incentives for taking risks, only criticism if something went wrong. Several justified their behavior as a means of avoiding conflicts in order to protect themselves and their unit. A member of the executive board admitted that half of his decisions were not in the company’s best interest. According to him, a no-risk mentality reigned in the company, so that he preferred to focus on his own chances and risks and weigh these carefully.

Last but not least, a few even said they would engage in decisions against the best interest of the company in seven to nine out of every 10 cases. Those were among the lowest level of managers. One of them explained the spirit of decision making as “better cover your ass.“

[Figure 6-1]

The defensiveness in this company is the rule rather than an exception. I have found similar cultures in other large companies. But it is not everywhere: Family businesses are one important exception. In a family- or owner-held company, shares are held by relatively few shareholders, typically by one or a few members of a family, unlike the stocks and other securities of publicly traded companies, which are spread across many investors. Most important, the corporate culture in family businesses is different. They are less anxious about gut feelings; if an error occurs, employees are not likely fired on the spot. Rather than being hidden deep down in the desk drawer, errors are talked about in order to learn from them. Family businesses resemble cockpit culture, while large publicly traded companies resemble emergency room culture (Chapter 5). The challenge for large companies is to better align the interests of their managers with those of the company, similar to how the interests of a family member are naturally aligned with those of the family business.

Companies could easily break through the taboo and calculate how much revenue they lose through a defensive culture. Reducing defensive decisions would provide an edge of advantage over competitors.  To improve its information flow, the leading technology provider used to send questionnaires with a hundred questions to its employees worldwide but didn’t really know what to do with the flood of responses. A first measure would be to replace this survey with only two questions: How often do you make defensive decisions? And what do you think could be done to change this? That could be a start for designing a new corporate culture.

Defensive Medicine

Pogo, a student of mine, once went whale watching on Cape Cod. It was a rough stormy day, and heavy waves hit the boat. When another wave came in, Pogo slipped on the wet surface, fell, and hurt himself. Another passenger kindly helped him up. He introduced himself as a lawyer.

“Have you been hurt?”

“Oh, my ankle hurts. But it will be ok. Thank you,” Pogo responded gratefully.

“Let’s sue the owner of the ship. If we lose, you won’t have to pay a thing. If we win, we’ll split the compensation.”

Pogo was perplexed.

“You can’t lose on that deal,” the lawyer stated, appealing to Pogo’s common sense.

“But it was my fault,” Pogo stuttered.

“Why don’t you let a judge find out?” the lawyer continued with impeccable logic.

“It really was my fault, not any one else’s.”

Eventually, Pogo declined the safe deal. He just felt it wasn’t right.

Not everyone would decline this opportunity. Whale watching boats are not the only location where tort lawyers crane their necks and sniff the wind for customers. Well-dressed hunters stroll through hospitals, race after emergency ambulances, and rent billboards for thousands of dollars a month to advertise their services. One might think that such in-depth malpractice surveillance can only be to the benefit of the public, but that’s a delusion. It has its price, and a heavy one – particularly in healthcare, where it undermines the relationship between doctor and patient.

Why Doctors Fear Patients

If you think your doctor recommends the best care for you, you may be right  – and lucky. Many doctors fear their patients might sue if a disease is overlooked or nothing aggressive is done. They feel they have no choice but to order unnecessary tests, drugs, or surgery, even if these may hurt the patient. They certainly wouldn’t recommend those treatments to their spouses and children, who are less of a legal threat.  In Switzerland, the rate of hysterectomy in the general population is 16 percent, whereas among doctors’ wives and female doctors it is only 10 percent.[2] In the US, where fear of litigation is higher, about one out of every three American women undergoes a hysterectomy, with numbers varying widely from region to region. For the total of approximately 600,000 hysterectomies performed every year, the majority of them are not clinically indicated. Half of these women also have their ovaries removed on this occasion, which is the equivalent of male castration, despite the growing evidence of severe debilitating consequences, including premature death. In total, an estimated 2.5 million unnecessary surgeries are performed on Americans every year.[3] No other country invades the bodies of its citizens so frequently.

There are more lawyers per capita in the U.S. than in any other country except Israel, and the number of law students is increasing steadily. But even in countries with less lust for litigation, such as Switzerland, defensive medicine is on the rise. Although only about half of 250 Swiss internists thought that the advantages of PSA screening outweigh its harms in men older than 50 years of age, 75 percent recommended regular PSA screening to these men. Why did they nevertheless recommend it? Many physicians said that they did so for legal reasons – to protect themselves against potential lawsuits, even though there is little danger of litigation in Switzerland.[4]

The problem in the US is that doctors can be punished even when they provide the best care for a patient, as the case of Dr. Merenstein shows.

One Million Dollars

In 2003, Daniel Merenstein, a young family physician in Virginia, was sued because he had not automatically ordered a PSA screening test for a highly educated fifty-three-year-old man.[5] Instead, he followed the recommendations of the National Cancer Institute and leading medical organizations and informed the patient about the pros and cons of screening. These organizations do not recommend routine screening because there is no proof that it saves lives, only proof that many men become incontinent and impotent from surgery or radiation after suspicious results. After hearing the evidence, the patient declined to take the test but later developed an incurable form of prostate cancer. The plaintiff’s attorney claimed that PSA tests were standard in the Commonwealth of Virginia, and four physicians testified that they routinely did the test without even informing their patients. The jury exonerated Merenstein but his residency was found liable for $1 million. Before the trial, Merenstein had believed in the value of keeping up with current medical science for the benefit of the patient. After the trial, he felt he had no choice but to make sure that every patient took the test, even at the risk of causing unnecessary harm. His clinic did not want to pay a second time. Merenstein then turned to defensive medicine: “I order more tests now, am more nervous around patients; I am not the doctors I should be.”[6]

Now we can define the practice:

Defensive medicine: A doctor orders tests or treatments that are not clinically indicated and might even harm the patient primarily because of fear of litigation.

The epigraph to this chapter reflects the very real feeling of fear that doctors like Merenstein feel about being sued and falling prey to an unfair malpractice tort process. But their fear of being sued for not doing caesarian sections subjects millions of women to unnecessary surgery. This is an ethical issue and a violation of women’s rights. Women who undergo C-sections have an increased risk of life-threatening complications such as blood clots, hemorrhage, and bowel obstruction.  They also experience less early contact with their babies and are hospitalized longer. The babies themselves are more likely to have breathing difficulties around the time of birth and asthma in childhood. On top of that, the total annual cost for medically unnecessary C-sections in the U.S. amounts to over $5 billion.[7] There is an ongoing debate whether the rising C-section rates are caused by predatory lawyers or by physicians’ fear of lawyers. Doctors accuse lawyers, and their subtle response is that the problem is not lawyers but doctors’ fear of them. This clever retort does not matter much for women whose C-section was superfluous.

Doctors are caught in a dilemma. They cannot avoid practicing defensive medicine, but they also cannot admit it. A doctor who did might lose patients, or at least their trust. At the same time, a doctor who bills health insurances such as Medicare for tests or procedures done for lawsuit protection is committing fraud in the US and other countries.

Many doctors are afraid of lawyers, and some are angry. That’s why they like lawyer jokes. Here is a joke that one surgeon told me with a malicious grin:

Question: What do you have if two lawyers are buried up to their necks in sand?

Answer: Not enough sand.

Ninety-three Percent of Doctors Practice Defensive Medicine

In Pennsylvania, 824 emergency doctors, radiologists, obstetricians/gynecologists, general surgeons, orthopedic surgeons, and neurosurgeons were asked whether they practice defensive medicine.[8]  All six specialties are at high risk of litigation. Ninety-three percent (!) of the doctors reported that they sometimes or often engage in defensive medicine. Since not everyone will admit to it, even anonymously, this figure may be lower than the actual numbers. What exactly do doctors do to protect themselves against the patient?

Here are the four favorite measures and the number of doctors who resort to them:

Kind of defensive medicine:                                        Number of doctors (percent)

  • Order more tests than medically indicated (e.g., imaging)                      405 (59)
  • Prescribe more medication (e.g., antibiotics)  than medically indicated      223 (33)
  • Refer patients to other specialists in unnecessary circumstances                                 349 (52)
  • Suggest invasive procedures (e.g., biopsies) to confirm diagnoses                    221 (32)

The most frequent unnecessary tests were computed tomographies (CTs), MRIs, and X-rays. Almost two thirds of emergency physicians reported doing this, half of general surgeons, orthopedic surgeons, and neurosurgeons, and a third of radiologists. Note that unlike an MRI, a CT is not merely expensive.  It can subject patients to a high dose of radiation, leading to cancer in a small number of them. In addition, more than a third of doctors reported that they avoid high-risk surgery, delivering infants, and caring for high-risk patients. Avoiding care is called negative defensive medicine, as opposed to positive defensive medicine in the form of excessive care. In each case, good care is thwarted by doctors’ collective anxiety.

 Trust In Health Care Will Eventually Break Down

Are patients aware that doctors practice defensive medicine? As far as I have seen, rarely. For instance, a study on defensive medicine in Spain reported that most doctors chose different treatments for their patients and for themselves.[9]  Perhaps doctors misjudged patients’ treatment preferences? No. Doctors predicted patients’ treatment preferences very well, but nevertheless chose treatments that protected them from litigation. Unaware of this, patients mistakenly believed that their doctor would have chosen the very same treatment in their place.

The doctor-patient relationship depends on personal bonding and trust. The more patients grow aware of defensive decision making, the more trust will be eroded. Parents will begin to question the motives behind their doctor recommending an MRI or CT scan for their child, and women will begin to second-guess why they should have a C-section. Patients will eventually begin to doubt doctors’ motivation and realize that more testing and treatment is not always better. In the end, there will be a breakdown of trust in health care, similar to what has happened in banking.

Altogether, three time bombs are ticking away in current health care systems that threaten to undermine trust. Physicians don’t do the best for their patients because they

1. practice defensive medicine (Self-defense),

2. do not understand health statistics (Innumeracy), or

3. pursue profit instead of virtue (Conflicts of interest).

Let’s call this the SIC syndrome of our health system. These conditions often work together in producing bad care. Innumeracy is the least known problem of the three (see chapters 9 and 10).  Conflicts of interest engendered by the changing orientation of medicine from virtue to profit have become an international phenomenon. In Western countries, for instance, it is legal for physicians to receive bribes in the form of cash by pharmaceutical companies for every new patient they put on their drugs. In China where most hospitals are government-owned and base salaries are quite low, physicians can enlarge their income substantially by selling drugs and imaging techniques. If they don’t, they lose money. These extra bonuses can be higher than their base salaries.[10]

Let’s have a closer look at excessive use of imaging, where all three components of the SIC syndrome play a role.

Take Care of Your Children

A boy has a runny nose. Just to be on the safe side (!), his mother brings him in for a CT scan. They sit in the waiting area until the technician calls them. Mom is on her cell phone; the boy is busy with his PlayStation. All three walk to the imaging room. Mom is still chatting on the phone while the technician tries to get her son’s attention, but he remains glued to his game. The frazzled technician yells at the mother: “I won’t do the scan twice!” CT has become so common that few pay attention anymore.

CT scans can be extremely valuable when used for what they are good at doing. But every year, an estimated one million U.S. children have unnecessary CT scans.[11] When a child has a stomach ache, a bump on the head, or pain, many parents think, better safe than sorry. “Vague abdominal pain” can get a child an abdominoplevic CT; “cough” may call for a chest CT. A major growth in CT use for children has been the diagnosis of appendicitis, despite the lack of evidence that it is more accurate than safer methods such as physical examination and ultrasound.[12]

An unnecessary CT scan is not simply a waste of money.  Radiation doses from CT are typically more than 100 times those of a chest X-ray.[13] The radiation exposure from one CT study involving several scans is about the same as for the average atomic-bomb survivor from Hiroshima and Nagasaki who was located one or two miles from “ground zero.”[14] As a consequence, an estimated 29,000 cancers result from the more than 70 million CT scans performed annually in the United States on children and adults.[15] Kids are more vulnerable to radiation’s effects than adults. Their brain tissue grows, their cells divide quickly, and their DNA is more easily damaged. 1,500 of the American children who receive CT scans each year may die from cancer later in life.[16]

Why don’t parents protect their children from unnecessary doses of radiation? They probably would if only they knew. Consider this opportunity:

Would you prefer a free total-body CT scan or to receive $1,000 in cash?

A representative sample of 500 Americans age 40 and over was given this choice. Three quarters of them wanted the CT scan and were willing to leave the money on the table.[17] Very few could imagine that there might be a downside, apart from the discomfort during the procedure. They were unaware that two out of hundred 45-year-olds who undergo annual full-body CT examinations up to age 75 will likely die from cancer because of the radiation.[18]

Patients who actually get scans are equally enthusiastic. Yale University researchers asked patients of all ages who had mild to moderate pain in the abdomen, pelvis, or flank. Virtually everyone believed that getting CT scans does not increase their lifetime risk of cancer.

How can so many patients not know? After all, everyone had a chance to talk to the emergency physicians who ordered the test.[19] The simple answer is that many doctors also don’t know. Nearly all of the Yale emergency department physicians who ordered the CT scans and over half of the radiologists who performed them also mistakenly believed that there is no lifetime risk of cancer. When the doctors were asked about the radiation dose, less than a quarter of emergency physicians and radiologists knew that it was 100 to 250 times higher than that of a chest X-ray. Most believed that it was only ten times as high, and some even thought it was lower. No wonder nearly all of the patients reported not being told.

Why are unnecessary CT scans performed on children? As we have just seen, many doctors and parents are ignorant of the impact of radiation from CT scans on children’s tissue. Conflicts of interest are another reason. In a fee-for-service system, clinics lose money if they do not perform unnecessary scans to “reassure” parents. A third reason is defensive decision making: Doctors order unnecessary CTs for fear of lawsuits by parents. Estimates are that one out of every thousand children who have had a CT scan develops a radiation-induced fatal cancer at some point in life.[20] But a doctor is unlikely to be sued when this happens 30 years later, after the child has grown up. Malpractice litigation can backfire.

What to Do?

We live in a health system where doctors do not have the same goals as patients. The doctors are not entirely to blame; after all, the patients are the ones who do the suing. Instead of complaining, we need to take more responsibility for our own health and that of one’s children.


When my daughter was six, we lived in Hyde Park, Chicago. One day, the two of us went for her first visit to the dentist. Let’s call him Dr. Push. My daughter had no pain; the only purpose was to get her acquainted with having her teeth checked. In such a situation, the FDA recommends a thorough clinical examination and warns against X-rays: “Radiographic screening for the purpose of detecting disease before clinical examination should not be performed.”[21] When I entered the dentist’s office, I found a small factory: one seat next to another, with Dr. Push scurrying around. When my daughter was finally seated in a chair that was much too high for her, a friendly nurse turned to her:

“We’re gonna make a nice X-ray picture of your teeth.”

“Sorry, that’s a misunderstanding,” I intervened, “She has no pains, no symptoms. It’s just to get a first examination.”

“We do X-rays all the time. Everyone gets an X-ray, so that the doctor can see what’s inside.” She told me this with a smile but in a firm tone.

“Look, she has no pains, no symptoms. There is no reason for an X-ray.”

Her smile froze. War clouds were gathering. “She has to have an X-ray. If you think that’s not a good idea, you will have to explain this to the doctor.”

“I would be happy to do so,” I responded.

At this she turned around and briskly walked away. After a while, she returned with Dr. Push.

“There is no reason to be afraid,” he assured my politely, “it’s just an X-ray. I need it so that I can see whether something is wrong with your daughter’s teeth.”

“True. But she has no pain. I just want you to do a clinical exam. It’s not in the interest of a little girl to get X-rays every time she visits a doctor.”

“Think for a moment,” he continued, “if there is something inside her teeth, I can’t see that with bare eyes. I could overlook something. You don’t want that, don’t you?” I felt the pressure mounting.  So I asked him: “Could you please tell me what’s known about the potential harms of dental X-rays for children? For instance, thyroid and brain cancer?”

He stared at me blankly.

“Or give me a reference so that I can check the evidence?” I asked.

Dr. Push didn’t respond to this either. “You will have to take the responsibility,” he threatened, not knowing the evidence.

“I’ll take it.”

He walked me to his office and handed over a sheet of paper. “Sign here.”

Dr. Push grew visibly angry after I asked for evidence he should know but didn’t. And I was furious with a man who X-rays children across the board, whether they have dental problems or not. Yet I shouldn’t have been. What really happened was that Dr. Push made me sign in order to protect himself against me. Parents’ litigation culture forces him to do so. Nonetheless, there is no excuse for routinely performing X-rays on children without knowing what harms they can cause.

Ask Your Doctors What They Would Do, Not What They Recommend

Patients can contribute their own share to better health care by asking for evidence. Patients also can contribute by refusing frivolous lawsuits, similar to what Pogo did. And there is a simple rule of thumb that I have found useful.

Around the age of 80, my mother began to lose her sight in her right eye. The diagnosis was a wet macular degeneration, a chronic eye disease caused by abnormal blood vessels that bring about blindness in the center field of vision (the macula). It often develops from dry macular degeneration, a less severe form. No therapy was known, but a treatment called photodynamic therapy was promoted that might stop further progression. A drug called verteprofin is injected, which concentrates in the abnormal blood vessels, and then laser light is used to activate the drug so that it can damage the abnormal blood vessels. I read the few available studies and found the evidence fairly ambiguous: It might help or hurt.

What to do? I located a medical expert who had performed a large number of photodynamic therapies. I explained my mother’s condition to him.

“What do you recommend?” I asked.

“If you ask me, I think your mother should try the treatment,” he explained.

At this moment, I realized I had asked the wrong question.

“I have only one mother,” I said, ”If it were your mother, what would you do?”

“Oh, I wouldn’t do it, no, I would tell her to wait,” he responded in a flash.

I told my mother, and she declined the treatment. Why would a doctor give one answer when I asked what he recommended, and another answer when I asked what he would do if it were his mother? The explanation is: His mother wouldn’t sue, but I might. Asking about his own mother shifted his perspective. Here is a rule of thumb that is often helpful:

  • Don’t ask your doctors what they recommend to you, ask them what they would do if it were their mother, brother, or child.

But there is a second part to my mother’s story that has nothing to do with defensive medicine but with  not understanding medical evidence. A few years later, she began to lose her sight in her other eye, for the same reason. This time she felt she should take her last chance, and I did not argue with her. After identifying an expert on photodynamic therapy in my mother’s hometown, I made the first contact. Here is our phone conversation:

“You need to understand that the treatment does not lead to a cure, all it can do is to stop further progression of blindness,” the expert explained in a patronizing tone.

“I understand.”

“And you need to understand that the success is not sure, but the probability is 50 percent that the progression will be stopped,” the expert continued.

“We’ll take the chance,” I confirmed.

“And you need to be aware that I may have to repeat the treatment four to five times, if it doesn’t work the first time.”

“Oh,” I said, “did the 50 percent refer to the first treatment or to the entire sequence of four or five?”

“To the first, and the same holds again for the second. Again 50 percent.”

“But that’s good news because is means that after five trials, it’s almost a sure thing – eventually in more than 90 percent of the patients the progression will be stopped because ….”

“No, no,” the expert interrupted me, “after all trials, we still have a probability of 50 percent.”

“But then the second and subsequent treatments would add nothing, isn’t that so?”

There was a long pause on the other side of the line. I could almost hear the specialist thinking.

“… Umm,” the specialist now saw the problem. “I need to go back and read the journal article.”

I did not press the matter further. A colleague of the specialist later told me that after this phone conversation, he rushed out to her and complained about me. I had injured his feeling of infallibility. But he went back and read. So did I – and found a few interesting things.

Note first that the specialist told me a single-event probability: the 50 percent chance that the progression will be stopped. As we have seen in Chapter 1, these are often confusing because the reference class is not specified. It could be all patients who undergo the treatment once, or those who undergo it several times. Here, it was about undergoing it several times. Next, a 50 percent chance of halting the progression of blindness is not informative in itself. It needs to be compared to the chance that the progression stops if one does nothing. The article reported that in 38 percent of patients the process also stops without the treatment.[22] That means that not 50 percent but only twelve percent of patients had a benefit. Then I learned that stopping progression does not mean that it really stops, but is defined as a loss of not more than three lines of visual acuity. Some of these patients who “benefited” according to the study had actually incurred further loss of vision. And then there were possible harms: Some of the patients reported abnormal vision and loss of vision after treatment. Last not least, in the conflicts of interest section, I found out that the study was financed by the same company that produced the expensive drug used in treatment and that many of the authors were company employees or paid consultants.

The second part of the story illustrates what a patient always should ask:

  • What is the benefit of the treatment?

– 50 percent of what? (e.g., of those who get treated once, or five times)

– How large was the “success” among those who were not treated?

– What precisely do you mean when you say “success”?

  • What are the harms of the treatment?
    •  Who financed the study?

I decided not to tell my mother about the specialist’s confusion. The end of the story was that I accompanied her to the treatment session, where the specialist was extremely polite to me, and at pains to point out that he’d read the article. My mother hoped so much that it would work. She was unlucky. Very soon after the treatment she went blind. In his records, the specialist listed my mother as a successful treatment.

Defensive Is Expensive

Back to defensive medicine. Patients might think that the threat of being sued is not taken seriously because doctors are insured. In fact, not all are. Some U.S. obstetricians no longer have insurance simply because it has become too expensive. The exorbitant fees for malpractice insurance add to the costs of health care, amounting to an estimated 10 percent of the health budget for hospitals and doctors.[23] For instance, plaintiffs received on average a compensation of nearly half a million dollars in more than half of closed U.S. malpractice claims. Most of these claims were resolved out of court. Indemnity and defense administration costs totaled $449 million.[24] The system’s overhead costs were exorbitant: 35% of the indemnity payments went to the plaintiffs’ attorneys; together with defense costs, the total costs of litigation amounted to 54% of the compensation paid to plaintiffs. In addition, doctors and plaintiffs had to spend a long and often strenuous time on each case: The average time between injury and resolution was five years. The longer a case lasts, the higher the costs and the lawyers’ earnings.

Being sued is about more than just money. Doctors lose time they could spend on caring for patients rather than on fighting for their reputation. A reform of the U.S. tort system is urgently needed to reduce this burden. One step would be to replace the custom-based legal standard of care with evidence-based liability. That would have protected Dr. Merenstein and allowed him to do the best for his patients. In my experience with training U.S. federal judges, the problem is that most of them do not realize the chasm between custom-based care and scientific evidence, that is, because many doctors are not aware of the available medical evidence, customary practices may be outdated. And judges themselves receive no training in law school to understand statistical evidence. As long as judges listen to what some local doctors ordinarily do rather than to what medical science knows, little will change.

Procedure Over Performance

Fear of blame, criticism, and litigation is the motivation for hiring the second-best, making second-best management decisions, and practicing defensive medicine. To avoid blame, people hide behind “safe” procedures. Rely on big names, do what everyone else does, and don’t listen to your intuition. Put your faith in tests and fancy technology, even if these are useless or harmful. Among doctors there is a saying: “No one is ever sued for overtreatment.” Even when a procedure is recognized as potentially harmful, there is a hesitation to act. Who wants to risk being sued by patients by standing up for their best interests?

The emotional fabric of defensive decisions differs from that of risk aversion. It can lead to excessive risk taking. If your intuition says that some investment is overvalued but you join because everyone else invests in it, you may take undue risks.  Part of the crowd behavior of financial investors that led to excessive risk taking in the recent financial crisis is a case in point.  The problem is not risk aversion, but lack of a positive error culture. People need to be encouraged to make occasional errors and take the responsibility in order to learn and achieve better overall performance.

Some time ago, an experienced headhunter visited me. Using his profound knowledge of the world of business, he had put about a thousand senior managers and CEOs into their positions. His world is changing. More and more, experience is replaced by psychometric tests administered by young psychologists who have never seen a company from the inside. I asked him why this change is happening. He said that those who make the hiring decisions fear they will be accountable. If a hire doesn’t turn out well and they have to admit that they trusted the intuition of an headhunter, that might count against them. But if they can point to having done psychometric tests that did not detect any problem, then they are on the safe side. Procedure protects. Defensive hiring, like defensive medicine, puts procedure over performance.


[1] Gigerenzer & Goldstein (2011).

[2] Domenighetti et al. (1993).

[3] Trunkey (2010, p. 421). On prophylactic removal of ovaries see Larson (2011).

[4] Steurer et al. (2009).

[5] Merenstein, (2004); Monahan (2007).

[6] Gigerenzer (2007, p. 161). A similar case is reported by Welch, Schwartz, & Woloshin (2011, p. 162). At the trial, the patient’s wife stood up, pointed at the doctor and yelled: “Murderer!”

[7] According to the Jackson Healthcare Report (2010) A costly defense: Physicians sound off on the high price of defensive medicine in the U. S., which can be downloaded at media/ 8968/ defensivemedicine_ebook_final.pdf

[8] Studdert et al. (2005).

[9] Garcia-Retamero & Galesic (2012).

[10] Chen (2007).

[11] Brenner & Hall (2007). The estimate is based on an ad hoc survey during a panel discussion at a meeting of pediatric radiologists. Lin (2010) presents similar estimates that 1 out of every 3 to 4 CT and MRI scans were unnecessary.

[12] Brenner & Hall (2007); Stephen et al. (2003).

[13] Brenner (2010); Picano & Matucci-Cerinic (2011).

[14] The effective radiation dose is measured in millisieverts (mSv). A useful way to understand radiation doses is to use natural background radiation as a benchmark. The mean dose absorbed by an average person from natural sources, such as radon in the home, is around 3 mSv. The mean dose among the survivors of the atomic bombs dropped on Japan was about 40 mSv (range: 5-100mSv). Depending on the machine settings and the organ studied, the typical radiation dose for a single CT scan is in the range of 10 to15 mSv. Because two or three scans are often performed on the same patient in the course of a diagnosis, the resulting radiation dose can be similar to what the average atomic-bomb survivors received and approximates their increased risk of cancer. Brenner (2010); Brenner & Hall (2007); Schwartz (2007).

[15] Berringon de González et al. (2009) estimated 72 million CT scans in the US in 2007, and the numbers have been rising from year to year.

[16] McCollough (2011).

[17] Schwartz, Woloshin, et al. (2004).

[18] Brenner & Elliston (2004).

[19] Lee et al (2004).

[20] Shah & Platt (2008). The risk of damage by CT scans is higher with lower age, for patients with large body mass index, for those undergoing multiphasic CT, and also for females. For instance, out of every 270 women who underwent coronary angiography CT at age 40, one is estimated to get cancer later in life from the radiation (Smith-Bindman et al. 2009).

[21] American Dental Association  & U.S. Department of Health and Human Services (2004).

[22] TAP Study Group (2001).

[23] Trunkey (2010, p. 424).

[24] Studdert et al. (2006).