Mark Crislip over at the Science Based Medicine Blog wrote that “in my experience” are the three most dangerous words in medicine. I won’t go so far as to say they are the most dangerous words in the physical therapy world but I do think that they pose a threat. A common example of this danger is when physical therapists use “in my experience” to justify a particular treatment philosophy even though it is not supported by science. One examples of this is the use of palpation and movement tests to diagnosis and guide treatment of the SI joint. Despite a large body of evidence questioning the reliability and validity of this method I still see it used all the time. When trying to discuss this topic with believers, I often run into the experience wall. “The literature may say the supine to sit test doesn’t work but I know it is effective because my patients get better.” Or I will hear how the literature is biased, out of touch with clinical reality, not applicable to their patients etc….. Many of these criticisms of the literature have elements of truth, however we need to hold clinical experience to the same standard. It is easy to criticize the literature while blindly trusting our own experiences. It takes great effort to critically appraise our experience (and the experience of others), looking for bias and logical fallacies. If you are looking for more information on the limits of human experience I suggest you take a look at these book (this, this and this). Feel free to share other resources in the comments section.
To explore the dangers and pit falls of experience in more depth we first need to understand what experience is. Clinical experience is comprised of:
1) the perception of clinical events (seeing, hearing, feeling)
2) the memories of those events
3) the interpretations of those perceptions (cause and effect, etc).
For example, I examine a patient (looking, hearing and feeling) and determine he has an anteriorly rotated right innominate. I remember that I have seen several patients who look just like this and when treated with a specific MET they got better. After the treatment the patient improves so I conclude that I was correct in my diagnosis and the treatment was effective.
Unfortunately humans are prone to make mistakes in all three of the above categories. To make matters worse we rarely notice those errors so we become very confident in the accuracy of our experiences. As a result, experience can become a barrier to accepting new evidence especially if it goes against our beliefs.
In upcoming posts I will explore each of these three categories in more depth. Stay tuned!