The Perils Of Living In A Grayscale Universe


Our professors in physical therapy school always tried to paint a rosy picture of how the real clinical world would be after we graduated.  Things would fall into neat categories, every condition had a specific type of treatment, and despite some surface level disagreement, there was always a solution to a patient’s problem. The illusion of certainty, of black and and white simplicity, was somewhat pervasive.  As a student, you don’t know any better.  Ambiguity wasn’t part of the discussion and would only serve to make things more complex.  

But after being immersed in the real world, you learn how fuzzy the picture really is. You learn that there is a range of opinions, both well supported by evidence and in spite of the evidence, on almost every clinical question you can think of.  Not everyone agrees, and often, people vehemently disagree.  The relative importance of various treatment approaches, the suspected causes of the conditions that we treat, the effectiveness of a given intervention, the language we use to communicate with patients, and even the overall value of physical therapy in health care is all up for debate.  

And despite the uncharted waters we are sailing through in medicine, our patients are eager to jump ship and swim towards someone who claims to have the perfect map. They can’t help it.  Human beings crave simplicity and assurance.  Some health care professionals, however, can be too confident they have the solution, either consciously or subconsciously.  It is in this gray area that practitioners of alternative medicine can hide. Steven Hatch, author of Snowball In a Blizzard: A Physician’s Notes on Uncertainty in Medicine, suggests that the first step in dealing with this uncertainty is to acknowledge it. 

Listening For Signals Among the Noise

Translating medical research into usable knowledge to change health outcomes is a complex task.  Steven Hatch suggests it is akin to playing a certain type of game:

“Picture a game in which we are testing you on your ability to recognize snowballs thrown through the air by some person, say, one hundred feet away, in the midst of a raging blizzard.  You don’t know how many snowballs we’re going to throw nor how often nor how fast or slow. You just have to look out into the whiteness and decide whether you see randomness or you have identified something as worthy of attention.” (Hatch, 9)  

This metaphor originates in radiology, where doctors examining mammograms have likened finding tumors to spotting snowballs in a blizzard.  Hatch argues this metaphor is useful for describing the day to day decisions healthcare professionals have to make with direct patient care and when making public health recommendations.  Simple questions have complex answers, and often it takes decades to get it right.  This is in stark contrast to general views of healthcare practitioners; we don’t always know what is going on, or have the best solutions, or make the best recommendations.  Luckily in physical therapy, the stakes are a bit lower and being wrong isn’t as much of a problem. But it doesn’t change the fact that the picture is not as clear as a patient might wish it was.  

Hatch illustrates this fuzziness with various examples throughout his book; the difficulty of making target blood pressure recommendations for various groups of people, the overall value of annual mammogram testing, the difficulty in treating and detecting lyme disease, the often overzealous reporting of trivial medical research, and the accuracy of diagnostics tests for various types of cancers, among others.  We see this uncertainty in physical therapy too.  

Uncertainty In Clinical Practice

Physical therapy is far from a complete science and we regularly operate in the realm of uncertainty.  We all want to be that expert detective that can determine exactly just what went wrong, and then be the hero in that patient’s life who can solve their problem. Clinical diagnosis is rarely that easy, and determining the ideal course of treatment can be even harder.  Uncertainty is constantly showing up in all phases of a patient’s episode of care.  It can be extremely frustrating to be unable to answer seemingly simple questions from patients.

Why am I in pain?   

When am I going to get better?

What do I need to do to fix it?

These questions have real answers, but being able to answer them with any amount of precision is the tricky part.  Obviously, there are simple cases that have simple answers, but this is not always the case.     

“Too often, we focus on transforming a patient’s gray-scale narrative into a black-and-white diagnosis that can be neatly categorized and labeled. The unintended consequence — an obsession with finding the right answer, at the risk of oversimplifying the richly iterative and evolutionary nature of clinical reasoning — is the very antithesis of humanistic, individualized patient-centered care.” (Simpkin, 1713)

Instead of going through differential diagnoses, and sorting patients into clearly labelled categories, perhaps we should be thinking a bit differently.  Probabilistic reasoning takes uncertainty into account and incorporates new information continuously.  Haskins sums it up thusly:

“Decision making in health care is increasingly informed by the incorporation of knowledge considered within a probabilistic framework. New information derived from the history, physical examination, and other investigations is used to revise prior beliefs about the likelihood of a given diagnosis or outcome by a magnitude proportional to the relative strength of that information.” (Haskins, 85)

While you can get very mathematical with it by actually calculating probabilities using the sensitivity and specificity of our clinical tests and the prevalence of certain conditions (Doust 1080), the general idea is what is important: We ought to scale the confidence in our convictions to the evidence in front of us, and revise as needed.  When we are wrong, we need to move on and pivot to other directions.  Understand that your beliefs are tentative and ought to change as the facts do.  

Exploiting Those In The Dark

The uncertainty that is prevalent in medicine provides an opportunity for alternative healthcare practitioners.  By utilizing this uncertainty, or in some cases exploiting it, practitioners can provide answers for patients with conditions that we simply aren’t that great at treating just yet.  Hatch illustrates this point by discussing the controversy surrounding “chronic lyme disease.”  There is a pseudoscientific medical group called the International Lyme And Associated Diseases Society (ILADS), that purports to take an alternative approach to treating patients with “chronic lyme disease,” which is not a recognized medical diagnosis but often given (wrongly) as a diagnosis to a set of general symptoms including sleepiness, mysterious and widespread pains, memory issues and many more that are associated with a few diagnoses that are difficult to make. The uncertainty surrounding lyme disease and other diseases that present similarly to it provides an opportunity for these groups to give a seemingly certain diagnosis and course of treatment.  And while the constellation of symptoms associated with a diagnosis of chronic lyme disease is mysterious, Hatch explains that the diagnosis is not medically accepted, and the purported treatment, prolonged antibiotics, does more harm than good (Hatch, 99-126).  

Examples like this can be seen in the physical therapy world too.  There is considerable debate among the profession as to the relative importance many things have to painful musculoskeletal problems including, but not limited to; fascia, trigger points, posture, spinal alignment, flexibility, soft tissue mobility, muscle strength, psychological state and many, many more.  Despite this debate, many therapists make their bones by focusing on one or two of these things most predominantly.  It is not hard to see advertisements on facebook for the newest device or exercise that fixes the newest problem you didn’t know was causing your back pain this whole time!  And if you don’t do something about this new problem, you are setting yourself up for a life of pain!  The exploitation of uncertainty, the scare tactics, and the general lack of appreciation of nuance can easily be seen.  

While I have already picked on craniosacral therapy in a previous article, I may just have to do it again.  Craniosacral therapy is purported to help with conditions that have a certain level of uncertainty with them either in diagnosis or treatment, including fibromyalgia, autism, and chronic fatigue syndrome.  It is professionally irresponsible to suggest that cranial bone alignment and cerebrospinal fluid flow have anything to do with these conditions, despite the uncertainty that doctors and researchers face with determining appropriate, evidence-based treatment.  While there are many factors that contribute to the painful conditions we treat, the reality is there are many dials we need to be able to tune effectively.  Determining the relative importance of each dial and how much it has to be tuned requires probabilistic reasoning, tentative conclusions, and being willing to admit we were wrong and start from scratch.  When faced with uncertainty, it is easy to latch on to explanations that are plausible, whether or not they are actually supported by the science.  And while the truth may be fuzzy, we ought to acknowledge that fuzziness instead of pretending that we can see the clear picture.

Intellectual Honesty

Engaging in scientific endeavors entails a tacit assumption that there is some true, objective reality that is waiting to be discovered and seen clearly.  What varies is how clear the average person thinks the picture is and how much time they spend looking at it.  

“They imply that physicians and human researchers are looking at the world exactly as it exists.  A more precise analogy is that we are looking at the world through cracked, warped, and foggy glass: there is some external reality out there, but getting at that reality is sometimes difficulty, and all of our speculations should be regarded with skepticism.” (Hatch, 205)

Patients may think we can see the picture very clearly.  Some science-deniers may think that it isn’t possible to see anything worthwhile.  And perhaps most insidiously, some healthcare practitioners might just take a quick glance and not go further.  They trust their initial vision, and don’t think that they may be mistaken.  With the reputation of the physical therapy profession on the line, that is no longer acceptable.  It is our ethical, moral, and professional duty to study this as deeply as we can and convey that information to our patients without distortion, exaggeration, or leaving anything out. And when things become fuzzy, it may be better to just let our patients know it.  We won’t always have the answers, but it would be disingenuous to do anything else.  


  1. Doust, J., (2009) Diagnosis in general practice: Using probabilistic reasoning. BMJ, Volume 339
  2. Haskins, R., (2014) Uncertainty in Clinical Prediction Rules: The Value of Credible Intervals. Journal Of Orthopedic And Sports Physical Therapy, Volume 44, Number 2
  3. Hatch, S., (2016) Snowball In A Blizzard: A Physician’s Notes on Uncertainty In Medicine
  4. Simpkin, A., (2016) Tolerating Uncertainty – The Next Medical Revolution?. The New England Journal Of Medicine, Volume 375, Number 18



1 Comment

  1. THANK YOU. Good grief, it’s nice to know there are other physical therapists out there who think like I do. I was a scientist before I was a PT, and I was fairly astounded at the amount of magical thinking that occurs in this profession. I’ve been told that objectively measuring things is “a waste of time” and “PT is an art” and “My clients get better so it must work” when I question dubious techniques and assumptions (ie visceral mobilization, “palpating the SIJ” and other such woo).


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