Ben Goldacre has made a point of exposing quack doctors and nutritionists, bogus credentialing programs, and biased scientific studies. He has also taken the media to task for its willingness to throw facts and proof out the window. But he's not here just to tell you what's wrong. Goldacre is here to teach you how to evaluate placebo effects, double-blind studies, and sample sizes, so that you can recognize bad science when you see it. You're about to feel a whole lot better.
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Table of Contents
1 - MATTER
DETOX AND THE THEATER OF GOO
IF IT’S NOT SCIENCE, WHAT IS IT?
2 - BRAIN GYM
3 - THE PROGENIUM XY COMPLEX
4 - HOMEOPATHY
WHAT IS HOMEOPATHY?
THE DILUTION PROBLEM
I DEMAND A FAIR TRIAL
5 - THE PLACEBO EFFECT
THE PLACEBO ON TRIAL
WHAT THE TREATMENT LOOKS LIKE
WHAT THE DOCTOR SAYS
MORE THAN MOLECULES?
AN ETHICAL PLACEBO?
6 - THE NONSENSE DU JOUR
THE FOUR KEY ERRORS
7 - NUTRITIONISTS
8 - THE DOCTOR WILL SUE YOU NOW
9 - IS MAINSTREAM MEDICINE EVIL?
THE PHARMACEUTICAL INDUSTRY
10 - WHY CLEVER PEOPLE BELIEVE STUPID THINGS
REGRESSION TO THE MEAN
THE BIAS TOWARD POSITIVE EVIDENCE
BIASED BY OUR PRIOR BELIEFS
11 - BAD STATS
THE BIGGEST STATISTIC
CHOOSING YOUR FIGURES
COCAINE FLOODS THE PLAYGROUND
OK, BACK TO AN EASY ONE
BEATING YOU UP
LOCKING YOU UP
LOSING THE LOTTERY
12 - THE MEDIA’S MMR HOAX
VACCINE SCARES IN CONTEXT
ANDREW WAKEFIELD AND HIS LANCET PAPER
THE STORY BEHIND THE PAPER
THE PRESS COVERAGE BEGINS
WHAT WAS IN THESE STORIES?
THE EVIDENCE ON MMR
SCIENTIFIC “EVIDENCE” IN THE MEDIA
WHAT THEY DIDN’T TELL YOU
OLD DISEASES RETURN
AND ANOTHER THING
BEN GOLDACRE BAD SCIENCE
PRAISE FOR BAD SCIENCE
FURTHER READING AND ACKNOWLEDGMENTS
I spend a lot of time talking to people who disagree with me—I would go so far as to say that it’s my favorite leisure activity—and repeatedly I meet individuals who are eager to share their views on science despite the fact that they have never done an experiment. They have never tested an idea for themselves, using their own hands, or seen the results of that test, using their own eyes, and they have never thought carefully about what those results mean for the idea they are testing, using their own brain. To these people “science” is a monolith, a mystery, and an authority, rather than a method.
Dismantling our early, more outrageous pseudoscientific claims is an excellent way to learn the basics of science, partly because science is largely about disproving theories, but also because the lack of scientific knowledge among miracle cure artistes, marketers, and journalists gives us some very simple ideas to test. Their knowledge of science is rudimentary, so as well as making basic errors of reasoning, they rely on notions like magnetism, oxygen, water, “energy,” and toxins—ideas from high school-level science and all very much within the realm of kitchen chemistry.
DETOX AND THE THEATER OF GOO
Since you’ll want your first experiment to be authentically messy, we’ll start with detox. Detox footbaths have been promoted uncritically in some very embarrassing articles in the New York Daily News, the Telegraph, the Mirror, The Sunday Times (London), GQ magazine, and various TV shows. Here is a taster from the New York Daily News: it’s a story about Ally Shapiro, a fourteen-year-old who went to a “detox” center run by Roni DeLuz, author of 21 Pounds in 21 Days: The Martha’s Vineyard Diet.
“The first day I did it,” says Shapiro, “the water was completely black by the end.” By day three, twenty minutes in the footbath generated a copper-colored sludge—the color of the flushed buildup from her joints related to arthritis, DeLuz explained. The hypothesis from these companies is very clear: your body is full of “toxins,” whatever those may be; your feet are filled with special “pores” (discovered by ancient Chinese scientists, no less); you put your feet in the bath, the toxins are extracted, and the water goes brown. Is the brown in the water because of the toxins? Or is that merely theater?
One way to test this is to go along and have an Aqua Detox treatment yourself at a health spa, beauty salon, or any of the thousands of places they are available online, and take your feet out of the bath when the therapist leaves the room. If the water goes brown without your feet in it, then it wasn’t your feet or your toxins that did it. That is a controlled experiment; everything is the same in both conditions, except for the presence or absence of your feet.
There are disadvantages with this experimental method (and there is an important lesson here—that we must often weigh up the benefits and practicalities of different forms of research, which will become important in later chapters). From a practical perspective, the “feet out” experiment involves subterfuge, which may make you uncomfortable. But it is also expensive: one session of Aqua Detox will cost more than the components to build your own detox device, a perfect model of the real one.
You will need:
- One car battery charger
- Two large nails
- Kitchen salt
- Warm water
- One Barbie doll
- A full analytic laboratory (optional)
This experiment involves electricity and water. In a world of hurricane hunters and volcanologists, we must accept that everyone sets their own level of risk tolerance. You might well give yourself a nasty electric shock if you perform this experiment at home, and it could easily blow the wiring in your house. It is not safe, but it is in some sense relevant to your understanding of MMR, homeopathy, postmodernist critiques of science, and the evils of big pharma. DO NOT BUILD IT.
When you switch your Barbie Detox machine on, you will see that the water goes brown, due to a very simple process called electrolysis; the iron electrodes rust, essentially, and the brown rust goes into the water. But there is something more happening in there, something you might half remember from chemistry at school. There is salt in the water. The proper scientific term for household salt is “sodium chloride”; in solution, this means that there are chloride ions floating around, which have a negative charge (and sodium ions, which have a positive charge). The red connector on your car battery charger is a “positive electrode,” and here negatively charged electrons are stolen away from the negatively charged chloride ions, resulting in the production of free chlorine gas.
So chlorine gas is given off by the Barbie Detox bath, and indeed by the Aqua Detox footbath, and the people who use this product have elegantly woven that distinctive chlorine aroma into their story: it’s the chemicals, they explain; it’s the chlorine coming out of your body, from all the plastic packaging on your food and all those years bathing in chemical swimming pools. “It has been interesting to see the color of the water change and smell the chlorine leaving my body,” says one testimonial for the similar product Emerald Detox. At another sales site: “The first time she tried the Q2 [Energy Spa], her business partner said his eyes were burning from all the chlorine that was coming out of her, leftover [sic] from her childhood and early adulthood.” All that chemically chlorine gas that has accumulated in your body over the years. It’s a frightening thought.
But there is something else we need to check. Are there toxins in the water? Here we encounter a new problem: What do they mean by toxins? I’ve asked the manufacturers of many detox products this question time and again, but they demur. They wave their hands, they talk about stressful modern lifestyles, they talk about pollution, they talk about junk food, but they will not tell me the name of a single chemical that I can measure. “What toxins are being extracted from the body with your treatment?” I ask. “Tell me what is in the water, and I will look for it in a laboratory.” I have never been given an answer.
After much of their hedging and fudging, I chose two chemicals pretty much at random: creatinine and urea. These are common breakdown products from your body’s metabolism, and your kidneys get rid of them in urine. Through a friend, I went for a genuine Aqua Detox treatment, took a sample of brown water, and used the disproportionately state-of-the-art analytic facilities of St. Mary’s Hospital in London to hunt for these two chemical “toxins.” There were no toxins in the water. Just lots of brown, rusty iron.
Now, with findings like these, scientists might take a step back and revise their ideas about what is going on with the footbaths. We don’t really expect the manufacturers to do that, but what they say in response to these findings is very interesting, at least to me, because it sets up a pattern that we will see repeated throughout the world of pseudoscience: instead of addressing the criticisms, or embracing the new findings in a new model, they seem to shift the goalposts and retreat, crucially, into untestable positions.
Some of them now deny that toxins come out in the footbath (which would stop me measuring them); your body is somehow informed that it is time to release toxins in the normal way—whatever that is, and whatever the toxins are—only more so. Some of them now admit that the water goes a bit brown without your feet in it, but “not as much.” Many of them tell lengthy stories about the “bioenergetic field,” which they say cannot be measured except by how well you are feeling. All of them talk about how stressful modern life is.
That may well be true. But it has nothing to do with their footbath, which is all about theater, and theater is the common theme for all detox products, as we shall see. On with the brown goo.
You might think that Hopi ear candles are easy targets. But their efficacy has still been cheerfully promoted by The Independent, The Observer, and the BBC, to name just a few respected British news outlets. They pop up endlessly in American local papers desperate to fill space, from the Alameda Times-Star to the Syracuse Post-Standard. Since journalists like to present themselves as authoritative purveyors of scientific information, I’ll let the internationally respected BBC explain how these hollow wax tubes, Hopi ear candles, will detox your body: “The candles work by vaporizing their ingredients once lit, causing convectional air flow towards the first chamber of the ear. The candle creates a mild suction which lets the vapors gently massage the eardrum and auditory canal. Once the candle is placed in the ear it forms a seal which enables wax and other impurities to be drawn out of the ear.” The proof comes when you open a candle up and discover that it is filled with a familiar waxy orange substance, which must surely be earwax. If you’d like to test this yourself, you will need: an ear, a clothespin, some poster putty, a dusty floor, some scissors, and two ear candles.
If you light one ear candle, and hold it over some dust, you will find little evidence of any suction. Before you rush to publish your finding in a peer-reviewed academic journal, someone has beaten you to it: a paper published in the medical journal Laryngoscope used expensive tympanometry equipment and found—as you have—that ear candles exert no suction. There is no truth to the claim that doctors dismiss alternative therapies out of hand.
But what if the wax and toxins are being drawn into the candle by some other, more esoteric route, as is often claimed?
For this you will need to do something called a controlled experiment, comparing the results of two different situations, where one is the experimental condition, the other is the control condition, and the only difference is the thing you’re interested in testing. This is why you have two candles.
Put one ear candle in someone’s ear, as per the manufacturer’s instructions, and leave it there until it burns down.1 Put the other candle in the clothespin, and stand it upright using the Blu-Tack; this is the “control arm” in your experiment. The point of a control is simple: we need to minimize the differences between the two setups, so that the only real difference between them is the single factor you’re studying, which in this case must be: “Is it my ear that produces the orange goo?”
Take your two candles back inside and cut them open. In the “ear” candle, you will find a waxy orange substance. In the “picnic table control,” you will find a waxy orange substance. There is only one internationally recognized method for identifying something as earwax: pick some up on the end of your finger, and touch it with your tongue. If your experiment had the same results as mine, both of them taste a lot like candle wax.
Does the ear candle remove earwax from your ears? You can’t tell, but a published study followed patients during a full program of ear candling and found no reduction. For all that you might have learned something useful here about the experimental method, there is something more significant you should have picked up: it is expensive, tedious, and time-consuming to test every whim concocted out of thin air by therapists selling unlikely miracle cures. But it can be done, and it is done.
DETOX PATCHES AND THE HASSLE BARRIER
Last in our brown sludge detox triptych comes the detox foot patch. These are available in most health food stores or from your local Avon lady (this is true). They look like teabags, with a foil backing that you stick onto your foot using an adhesive edging, before you get into bed. When you wake up the next morning, there is a strange-smelling, sticky brown sludge attached to the bottom of your foot and inside the teabag. This sludge—you may spot a pattern here—is said to be “toxins.” Except it’s not. By now you can probably come up with a quick experiment to show that. I’ll give you one option in a footnote.2
An experiment is one way of determining whether an observable effect—sludge—is related to a given process. But you can also pull things apart on a more theoretical level. If you examine the list of ingredients in these patches, you will see that they have been very carefully designed.
The first thing on the list is “pyroligneous acid,” or wood vinegar. This is a brown powder that is highly hygroscopic, a word that simply means it attracts and absorbs water, like those little silica bags that come in electronic equipment packaging. If there is any moisture around, wood vinegar will absorb it and make a brown mush that feels warm against your skin.
What is the other major ingredient, impressively listed as “hydrolyzed carbohydrate”? A carbohydrate is a long string of sugar molecules all stuck together. Starch is a carbohydrate, for example, and in your body this is broken down gradually into the individual sugar molecules by your digestive enzymes, so that you can absorb it. The process of breaking down a carbohydrate molecule into its individual sugars is called hydrolysis. So “hydrolyzed carbohydrate,” as you might have worked out by now, for all that it sounds sciencey, basically means “sugar.” Obviously sugar goes sticky in sweat.
Is there anything more to these patches than that? Yes. There is a new device, which we should call the hassle barrier, another recurring theme in the more advanced forms of foolishness that we shall be reviewing later. There are huge numbers of different brands, and many of them offer excellent and lengthy documents full of science to prove that they work: they have diagrams and graphs and the appearance of scienciness, but the key elements are missing. There are experiments, they say, which prove that detox patches do something . . . but they don’t tell you what these experiments consisted of, or what their “methods” were; they offer only decorous graphs of “results.”
To focus on the methods is to miss the point of these apparent “experiments”: they aren’t about the methods; they’re about the positive result, the graph, and the appearance of science. These are superficially plausible totems to frighten off a questioning journalist, a hassle barrier, and this is another recurring theme, which we will see—in more complex forms—around many of the more advanced areas of bad science. You will come to love the details.
IF IT’S NOT SCIENCE, WHAT IS IT?
But there is something important happening here, with detox, and I don’t think it’s enough just to say, “All this is nonsense.” The detox phenomenon is interesting because it represents one of the most grandiose innovations of marketers, lifestyle gurus, and alternative therapists: the invention of a whole new physiological process. In terms of basic human biochemistry, detox is a meaningless concept. It doesn’t cleave nature at the joints. There is nothing on the “detox system” in a medical textbook. That burgers and beer can have negative effects on your body is certainly true, for a number of reasons; but the notion that they leave a specific residue, which can be extruded by a specific process, a physiological system called detox, is a marketing invention.
If you look at a metabolic flowchart, the gigantic wall-size maps of all the molecules in your body, detailing the way that food is broken down into its constituent parts, and then those components are converted between each other, and then those new building blocks are assembled into muscle, and bone, and tongue, and bile, and sweat, and booger, and hair, and skin, and sperm, and brain, and everything that makes you you, it’s hard to pick out one thing that is the “detox system.”
Because it has no scientific meaning, detox is much better understood as a cultural product. Like the best pseudoscientific inventions, it deliberately blends useful common sense with outlandish, medicalized fantasy. In some respects, how much you buy into this reflects how self-dramatizing you want to be or, in less damning terms, how much you enjoy ritual in your daily life. When I go through busy periods of partying, drinking, sleep deprivation, and convenience eating, I usually decide—eventually—that I need a bit of a rest. So I have a few nights in, reading at home, and eating more salad than usual. Models and celebrities, meanwhile, “detox” with Master Cleanse and the Fruit Flush Diet.
On one thing we must be absolutely clear, because this is a recurring theme throughout the world of bad science: there is nothing wrong with the notion of eating healthily and abstaining from various risk factors for ill health like excessive alcohol use. But that is not what detox is about; these are quick-fix health drives, constructed from the outset as short term, while lifestyle risk factors for ill health have their impact over a lifetime. But I am even willing to agree that some people might try a five-day detox and remember (or even learn) what it’s like to eat vegetables, and that gets no criticism from me.
What’s wrong is to pretend that these rituals are based in science or even that they are new. Almost every religion and culture have some form of purification or abstinence ritual, with fasting, a change in diet, bathing, or any number of other interventions, most of which are dressed up in mumbo jumbo. They’re not presented as science, because they come from an era before scientific terms entered the lexicon, but still: Yom Kippur in Judaism, Ramadan in Islam, and all manner of other similar rituals in Christianity, Hinduism, the Baha’i faith, Buddhism, and Jainism are each about abstinence and purification (among other things). Such rituals, like detox regimes, are conspicuously and—to some believers too, I’m sure—spuriously precise. Hindu fasts, for example, if strictly observed, run from the previous day’s sunset until forty-eight minutes after the next day’s sunrise.
Purification and redemption are such recurrent themes in ritual because there is a clear and ubiquitous need for them; we all do regrettable things as a result of our own circumstances, and new rituals are frequently invented in response to new circumstances. In Angola and Mozambique, purification and cleansing rituals have arisen for children affected by war, particularly former child soldiers. These are healing rituals, in which the child is purged and purified of sin and guilt, of the “contamination” of war and death (contamination is a recurring metaphor in all cultures, for obvious reasons); the child is also protected from the consequences of his previous actions, which is to say, he is protected from retaliation by the avenging spirits of those he has killed. As a World Bank report put it in 1999:
These cleansing and purification rituals for child soldiers have the appearance of what anthropologists call rites of transition. That is, the child undergoes a symbolic change of status from someone who has existed in a realm of sanctioned norm-violation or norm-suspension (i.e. killing, war) to someone who must now live in a realm of peaceful behavioral and social norms, and conform to these.
I don’t think I’m stretching this too far. In what we call the developed Western world, we seek redemption and purification from the more extreme forms of our material indulgence: we fill our faces with drugs, drink, bad food, and other indulgences, we know it’s wrong, and we crave ritualistic protection from the consequences, a public “transitional ritual” commemorating our return to healthier behavioral norms.
The presentation of these purification diets and rituals has always been a product of their time and place, and now that science is our dominant explanatory framework for the natural and moral world, for right or wrong, it’s natural that we should bolt a bastardized pseudoscientific justification onto our redemption. Like so much of the nonsense in bad science, “detox” pseudoscience isn’t something done to us, by venal and exploitative outsiders; it is a cultural product, a recurring theme, and we do it to ourselves.
Copyright 2010 Ben Goldacre
Table of Contents
1 Matter 3
2 Brain Gym 15
3 The Progenium XY Complex 23
4 Homeopathy 30
5 The Placebo Effect 65
6 The Nonsense du Jour 87
7 Nutritionists 112
8 The Doctor Will Sue You Now 131
9 Is Mainstream Medicine Evil" 147
10 Why Clever People Believe Stupid Things 172
11 Bad Stats 186
12 The Media's MMR Hoax 208
And Another Thing 253
Further Reading and Acknowledgments 271