Anecdotal evidence against anecdotal evidence
By Tammy Buchli, Science & Reason in Hampton Roads
Article ID: 1234
Everybody has a story, and most people are eager to share their stories with anyone who will listen. A problem is that some like to use their stories as scientific evidence. Alternative medicine advocates, in particular, love to use anecdotes in order to justify the efficacy of their wares. After all, if something seems to work, it’s pretty easy to make the claim that it actually is working. The problem, of course, is that anecdotal evidence can be deceptive.
My daughter, now 21 years old, is disabled with cerebral palsy. She was diagnosed at 8 months old, and her level of disability is fairly severe. I soon discovered that having a disabled child made us attractive to people attempting to sell alternative cures. This was particularly obvious after we got our first home computer. Typing ‘cerebral palsy‘ into a search engine unleashed a deluge of snake oil salesmen, each of whom urged us to buy their product or service and offered a long list of satisfied customers as proof that they could help our daughter. We chose instead to limit our daughter’s medical care to therapies which had been vetted by science. But still… sometimes those alternative therapies seemed mighty attractive - some of these things did seem to work for some people. Were we wrong not to take the chance that some of these cures might help our daughter? Finally, though, an event occurred which convinced me of the error of using anecdotal evidence as the sole claim for the efficacy of a treatment or therapy. This is our story - what I like to call anecdotal evidence against anecdotal evidence.
When our daughter was nine years old, she had a major orthopedic surgery on her legs. This was her second such surgery and her recovery was slow and difficult, as is common with repeat orthopedic surgeries. She was in a body cast for six weeks, and then underwent extensive physical therapy for a year after the cast was removed. The results of the surgery were somewhat disappointing - one year after the surgery, she seemed no better off than she had been before it. He legs were straighter and her posture better, but functionally she was about the same. She could use crutches to a limited degree in our home, but used a wheelchair to and from school and everywhere else. We assumed that she had simply found her level; we stopped the physical therapy and life went on.
Eight months later, however, something happened. Our daughter suddenly started to improve. We later discovered that bursts of spontaneous improvement are not uncommon in children with cerebral palsy. But at the time, her progress seemed almost miraculous to us. Within just a few months time, she made major, noticeable advances in almost every aspect of her physicality. Her balance, strength and muscle tone improved; as did her posture and gait. She started using her crutches exclusively, and learned to walk with one crutch instead of two. Within a year, her wheelchair was relegated to the attic. And all these changes took place despite a complete lack of any kind of therapeutic intervention.
Now, what if during the year immediately following her difficult surgery, we had become discouraged and turned to craniosacral therapy, or biofeedback, or hyperbaric oxygen chamber therapy? What if we had sold the dog and a kidney apiece to finance a trip to Poland for Adeli Suit therapy, or to Lourdes for a faith healing? Then those things would have gotten the credit for her improvement, even though they would clearly have had nothing to do with it.
That’s the problem with using anecdotes as evidence - they are stories, not facts. Stories are fun to tell and fun to hear, but they don’t prove anything on their own. Anecdotal evidence can be useful as a starting point for research, but it has to be backed up with randomized, controlled clinical trials if it is to have any real value.
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