I recently wrote an article for a community newspaper attempting to explain to scientifically naive readers why testimonial “evidence” is unreliable; unfortunately, they decided not to print it. I considered using it here, but I thought it was too elementary for this audience. I have changed my mind and I am offering it below (with apologies to the majority of our readers), because it seems a few of our readers still don’t “get” why we have to use rigorous science to evaluate claims. People can be fooled, folks. All people. That includes me and it includes you. Richard Feynman said
The first principle is that you must not fool yourself–and you are the easiest person to fool.
Science is the only way to correct for our errors of perception and of attribution. It is the only way to make sure we are not fooling ourselves. Either Science-Based Medicine has not done a good job of explaining these vital facts, or some of our readers are unable or unwilling to understand our explanations.
Our commenters still frequently offer testimonials about how some CAM method “really worked for me.” They fail to understand that they have no basis for claiming that it “worked.” All they can really claim is that they observed an improvement following the treatment. That could indicate a real effect or it could indicate an inaccurate observation or it could indicate a post hoc ergo propter hoc error, a false assumption that temporal correlation meant causation. Such observations are only a starting point: we need to do science to find out what the observations mean. (more…)
Chiropractic originated in 1895 when D.D. Palmer claimed to have restored deaf janitor Harvey Lillard’s hearing by manipulating his spine. This makes no anatomical sense, and few if any chiropractors claim to be able to reverse deafness today. But now a chiropractic website is attempting to vindicate D. D. Palmer. They list deafness among a long (wrong) list of “Conditions That Respond Well to Chiropractic”
They list 6 supporting studies. Three are case reports, two are case series, and one is a review of the literature that is labeled in its title as “A Search to Validate” D.D. Palmer. (more…)
There are four main principles in medical ethics:
Autonomy means the patient has the right to consent to treatment or to reject it. Autonomy has to be balanced against the good of society. What if a patient’s rejection of treatment or quarantine allows an epidemic to spread? Beneficence means we should do what is best for the patient. Non-maleficence means “First do no harm.” Justice applies to conundrums like how to provide kidney dialysis and organ transplants equitably in a society that can’t afford to treat everyone with expensive high-tech treatments or where the rich can afford better treatment than the poor.
Medical ethicist Ronald Munson has written a fascinating book entitled The Woman Who Decided to Die: Challenges and Choices at the Edges of Medicine. His clinical vignettes vividly illustrate the difficult decisions that must be made when science-based medicine runs up against the harsh practical reality of ethical dilemmas. (more…)
Alternative medicine by definition is medicine that has not been shown to work any better than placebo. Patients think they are helped by alternative medicine. Placebos, by definition, do “please” patients. We would all like to please our patients, but we don’t want to lie to them. Is there a compromise? Is there a way we can ethically elicit the same placebo response that alternative theorists elicit by telling their patients fairy tales about qi, subluxations, or the memory of water?
Psychiatrist Morgan Levy has written a book entitled Placebo Medicine. It’s available free online. In it, he makes an intriguing case for incorporating the best alternative medicine placebo treatments into mainstream medicine.
In a light, entertaining style, he covers the placebo effect, suggestibility, and the foibles of the human thought processes that allow us to believe a treatment works when it doesn’t.
“Thinking like a human” is not a logical way to think but it is not a stupid way to think either. You could say that our thinking is intelligently illogical. Millions of years of evolution did not result in humans that think like a computer. It is precisely because we think in an intelligently illogical way that our predecessors were able to survive… [by acting on quick assumptions rather than waiting for comprehensive, definitive data]… We have evolved to survive, not to play chess.
He offers evidence from scientific studies indicating that belief in a treatment and the power of suggestion can have actual physiologic consequences such as production of endorphins or changes on brain imaging studies. He spices his narrative with colorful stories, including anecdotes from his own sex life and an impassioned plea (tongue in cheek?) for everyone to drink coffee for its proven benefits. (more…)
Tylenol (acetaminophen, also known as paracetamol outside the US) has been in the news recently. Most of the stories I’ve seen have been accurate, but I’ve run across a couple of people who misunderstood what they read. I thought I’d try to put the record straight.
An FDA advisory panel has recommended reducing the maximum allowed single dose from 1000 mg to 650 mg in over-the-counter acetaminophen products. The 1000 mg dose would be available by prescription only. They also recommended eliminating painkillers like Percocet and Vicodin that contain a combination of a narcotic and acetaminophen. They did not recommend removing acetaminophen from over-the-counter cold remedies, cough medicines and similar products that combine acetaminophen with other drugs. Advisory panel recommendations are not binding, but the FDA usually follows them.
Some people got the impression that the FDA had just discovered that acetaminophen can be dangerous. No, we always knew that. The danger is when you take too much: it can damage the liver. The “new” information is just that acetaminophen overdose is now the leading cause of liver damage, causing an estimated 1600 cases of liver failure each year. (more…)
So many of the posts on this blog are critical and deal with examples of poor science or other problems. I’d like to offer a breath of fresh air in the form of a book by Mark Sloan, MD: Birth Day: A Pediatrician Explores the Science, the History, and the Wonder of Childbirth.
It is a very positive book. Sloan has attended over 3000 deliveries but he has not lost his sense of wonder. He tells us what life is like in the womb – how much the fetus can see and hear – and smell! He explains the labor process. He explains how a fetus has to rapidly adapt to life outside the womb with a number of physiologic changes. He reflects the joy of bringing a new life into a family, and the experience of becoming a father. He delves into the history of childbirth, with fascinating anecdotes about “salting” newborns, Queen Victoria’s influence on obstetric analgesia, and the attempt to keep forceps a proprietary secret of one family.
He shows the many contributions science has made to childbirth, some of the mistakes it made along the way, and how it corrected those mistakes. (more…)
A study published in Alternative Therapies in Health and Medicine is being cited as evidence for the efficacy of healing touch (HT). It enrolled 237 subjects who were scheduled for coronary bypass, randomized them to receive HT, a visitor, or no treatment; and found that HT was associated with a greater decrease in anxiety and shorter hospital stays.
This study is a good example of what I have called “Tooth Fairy Science.” You can study how much money the Tooth Fairy leaves in different situations (first vs. last tooth, age of child, tooth in baggie vs. tooth wrapped in Kleenex, etc.), and your results can be replicable and statistically significant, and you can think you have learned something about the Tooth Fairy; but your results don’t mean what you think they do because you didn’t stop to find out whether the Tooth Fairy was real or whether some more mundane explanation (parents) might account for the phenomenon. (more…)
It’s easy to think of medical tests as black and white. If the test is positive, you have the disease; if it’s negative, you don’t. Even good clinicians sometimes fall into that trap. Based on the pre-test probability of the disease, a positive test result only increases the probability by a variable amount. An example: if the probability that a patient has a pulmonary embolus (based on symptoms and physical findings) is 10% and you do a D-dimer test, a positive result raises the probability of PE to 17% and a negative result lowers it to 0.2%.
Even something as simple as a throat culture for strep throat can be misleading. It’s possible to have a positive culture because you happen to be an asymptomatic strep carrier, while your current symptoms of fever and sore throat are actually due to a virus. Not to mention all the things that might have gone wrong in the lab: a mix-up of specimens, contamination, inaccurate recording…
Mammography is widely used to screen for breast cancer. Most patients and even some doctors think that if you have a positive mammogram you almost certainly have breast cancer. Not true. A positive result actually means the patient has about a 10% chance of cancer. 9 out of 10 positives are false positives.
But women don’t just get one mammogram. They get them every year or two. After 3 mammograms, 18% of women will have had a false positive. After ten exams, the rate rises to 49.1%. In a study of 2400 women who had an average of 4 mammograms over a 10 year period, the false positive tests led to 870 outpatient appointments, 539 diagnostic mammograms, 186 ultrasound examinations, 188 biopsies, and 1 hospitalization. There are also concerns about changes in behavior and psychological wellbeing following false positives.
Until recently, no one had looked at the cumulative incidence of false positives from other cancer screening tests. A new study in the Annals of Family Medicine has done just that. (more…)
In May 2008, the article “Why the NIH Trial to Assess Chelation Therapy (TACT) Should Be Abandoned” was published online in the Medscape Journal of Medicine. The authors included two of our own SBM bloggers, Kimball Atwood and Wallace Sampson, along with Elizabeth Woeckner and Robert Baratz. It showed that the existing evidence on treating heart disease with IV chelation did not justify further study, and that the TACT trial was questionable on several ethical points. Their ethical concerns were taken seriously enough that enrollment in the trial was put on hold pending an investigation. It has now been re-opened after a few band-aids were applied to the ethical concerns. The scientific concerns were never addressed.
I have seen many critiques of the Atwood study, and not a single one has offered any cogent criticism of its factual content or reasoning. Most of them could have been written by someone who had not bothered to read beyond the title. Their arguments can be boiled down to a few puerile points that can be further simplified to:
(1) I believe the testimonial evidence that chelation works.
(2) Atwood and his co-authors are bad guys.
Now Beth Clay has chimed in with an article entitled “Study of Chelation Therapy Should Not Be Abandoned.” I found it truly painful to read, but even the worst has some value as a bad example. Clay’s article could be used for a game of “Count the Errors.” I will point out some of them below. (more…)
A new book, Science Under Siege: Defending Science, Exposing Pseudoscience addresses many of the issues near and dear to the hearts of SBM bloggers and readers. A compilation of some of the best writing from the last few years of Skeptical Inquirer magazine, it’s not only good reading but can serve as a useful reference.
Skeptical Inquirer is the official magazine of what was formerly called The Committee for the Skeptical Investigation of Claims of the Paranormal (CSICOP). It was formed in 1976 and in its early days it concentrated on things like Bigfoot, UFOs and psychics. It has morphed into the Committee for Skeptical Inquiry and the magazine is now described on its cover as “The Magazine for Science and Reason.” It has gone way beyond paranormal claims to address everything from intelligent design to AIDS denial. In the 3 decades of its existence it has performed an invaluable service by investigating alleged phenomena and testing claims scientifically, providing natural explanations for weird observations, refuting pseudoscientific arguments, and teaching people how science works and how to think critically.
We now have many skeptical magazines, including Michael Shermer’s Skeptic in the US and similarly named publications in the UK, Australia and elsewhere. But Skeptical Inquirer was the first. It was the trailblazer and set the standard.
The word “skeptic” has negative connotations for some. But it is really a positive, inquisitive, reality-based approach to all aspects of life. A skeptic is a person who asks for evidence before accepting a belief and who asks if there could be another explanation other than the first one that is offered. Scientists are skeptics. Skeptics think scientifically. (more…)