What is ‘evidence’?

The modern day world of medicine and science seems to revolve around this one word ‘evidence’. We have for example, evidenced-based medicine, evidence-based practice, best-evidence medical education, evidence guided education and the question – “what is the evidence for that?” dominates the worlds of academia, research and clinical practice. 

There is a faction within science and medicine that is purporting that no treatments or modalities should be available unless they are supported by ‘evidence’.  This seems to be a reasonable and logical suggestion, so that people can be assured of the treatment they are receiving. 

But what if specific factions within medicine and science are more concerned with maintaining power and control over knowledge and thus support a narrow and restrictive view of what is ‘evidence’ in order to maintain their power and control, rather than being truly concerned with the welfare of mankind? 

What if there are other forms of evidence that are currently dismissed by those in science and academia not just because they do not fit into their narrow way of understanding evidence based on a hierarchy of study design, but because to accept them would mean they could no longer dominate the conversation, no longer have power and control over knowledge and evidence? 

And so the question arises – what is ‘evidence’? Given the demand for ‘evidence’ it is vital we explore and know what it is and consider the possibility that there is more to evidence than we have been led to believe.

The randomised double blind controlled trial (RCT) and subsequent meta-analyses of trial data is currently considered by many to be the ‘Gold standard’ when it comes to evidence and that unless treatments or modalities have this type of evidence they should not be supported or funded. Whilst this might be reasonably straightforward for a medication trial, it is clear that there are certain fields where such trials are just not feasible nor appropriate – and where different forms of evidence are called for (Thistlethwaite).  Different purposes call for different sources and types of evidence and it is important we do not restrict ‘evidence’ to a one form or definition only.

Increasingly people are questioning the validity of the RCT being the gold standard and realising it is definitely not the only form of valid evidence. Furthermore, the general adoption of the double blind RCT was itself based more on theory rather than a compelling body of data (or evidence) and indeed attempts to systematically investigate its assumed objectivity have been relatively scarce (Kaptchuk). How ironic that the Gold standard for ‘evidence’ is itself not supported by that same ‘evidence’? Giving the RCT a sanctified status within science research is misplaced – it is definitely not infallible ( Ioannaidis) nor is it as methodologically fullproof as it is assumed to be and in many instances it is simply not the correct method to use.

All evidence is context dependent, research data is inanimate until processed through a human mediator to give it action, agency and narrative. Research does not speak for itself and only becomes knowledge or evidence that provides meaning or motivation when activated by a human being, who themselves have a historicity that can influence and shape the way the data is portrayed. Without understanding the different influences on what is evidence – we can be easily fooled into thinking and believing it is black and white whereas it often has many shades of grey.

Historically in medicine ‘evidence’ for the efficacy of treatments accumulated through the practice of trial and observation – applying a treatment or operation and observing the outcome. Indeed research today is often informed by such observations – and we then use research to gather the data and the statistics to confirm what we have already observed! 

Indeed we use the power of observation in our own lives every day to make decisions based on the evidence we have received from our observations and Scriven makes the point that perhaps this is the true gold standard? 

The Body as Evidence

Ultimately, when we consider what is evidence we also need to ask what is the evidence for? What is our overall purpose within medicine in performing research, drug trials and so forth? Is it to enable people to live with a greater quality of life in their own bodies? To be healthy, vital and free of illness and disease or alleviated from the suffering associated with illness and disease? If this is so then would it not be reasonable to suggest that the body itself is a valid form and means of evidence? It is through the body that we know when we are in pain or unwell, it is through the body that we know when we feel vital, energetic and healthy. So this being the case, why then do we ignore the personal evidence of a person’s lived experience in their own body by calling it anecdote? 

Why do we only consider anecdotes valid when they are collected together to form a body of data we then call evidence? We had it driven into us at medical school that the key to understanding and knowing what is making a patient sick is in their history – the story they tell from their own bodies about what is happening in their own bodies. Why is that only considered valid when someone is sick? Why are we so quick to ignore and dismiss this ‘evidence’ when people report what happens when, for example, they adjust their lifestyle – their diet, sleep, emotional wellbeing and so forth?  If we valued and listened to the evidence of our body we would know with only one hangover, and no formal research required, that alcohol was harming for the body. A truth that many prefer to ignore and dismiss, so as not to relinquish their regular tipple or binge. A life without something to take the edge off it seems too scary a prospect for many. 

What if we accepted that everyone’s body is a valid form of evidence, indeed a ‘body of evidence’ that reveals the consequences of the choices of the life lived thus far?  What if we empowered people to know this for themselves so that they can learn how to read their own body, gather their own evidence so that they can make more healthy choices? 

Evidence is not gathered for an end in itself but is to be applied and actioned – every day we get to feel the evidence in our own bodies of how we have lived that day and by making different choices and feeling their consequences in our own bodies we become a living, breathing, walking experiment in action – continuously observing and feeling the consequences of our choices on our bodies and modifying the experiment accordingly. 

It is increasingly clear that there is more to evidence than the ‘evidence’ suggests. The RCT is not the only means of valid evidence and to persist in this misbelief is to deny the real benefits that can be derived by using other forms of evidence – including that obtained through the simple principle of detached observation.  



Ioannidis JP, Why most published research findings are false. PLOS Med 2005 Aug 2 (8): e124

Kaptchuk TJ. The double-blind, randomized, placebo-controlled trial: gold standard or golden calf? J Clin Epidemiol. 2001 Jun;54(6):541-9.

Scriven M. A Summative Evaluation of RCT Methodology: And an Alternative Approach to Causal Research. Journal of Multidisciplinary Evaluation, Vol 5, No 9 pp11-24 http://journals.sfu.ca/jmde/index.php/jmde_1/article/view/160/186

Thistlethwaite J, Davies H, Dornan T, Greenhalgh T, Hammick M, Scalese R. What is evidence? Reflections on the AMEE symposium, Vienna, August 2011. Medical Teacher 2012 1-4 Early online


  • Reply
    Joseph Barker
    2nd February 2016 at 12:01 am

    Brilliantly written Eunice. “Every day we get to feel the evidence in our own bodies of how we have lived that day” This turns the tables to show that a body of evidence begins with physical being and the story all of ours bodies collectively have to tell.

  • Reply
    jeanette macdonald
    28th January 2016 at 7:15 pm

    I really like this paragraph Eunice, “Evidence is not gathered for an end in itself but is to be applied and actioned – every day we get to feel the evidence in our own bodies of how we have lived that day and by making different choices and feeling their consequences in our own bodies we become a living, breathing, walking experiment in action – continuously observing and feeling the consequences of our choices on our bodies and modifying the experiment accordingly”
    How awesome it would be if every’body’realised they were their own science project, a living, breathing, walking experiment. How rich and interesting the research to be done,and how much more purposeful life could become.
    We get presented every day with what works for us and what doesn’t. Oftentimes we persist with what doesn’t but the body in its infinite wisdom continues to offer us the evidence of our choices.

  • Reply
    24th January 2016 at 10:29 pm

    I really enjoyed your article Eunice it puts the evidence concept into perspective very clearly. What I have learnt about what foods my body best tolerates has come from my own observations/experiments. Which has proven to me that we are all very different when it comes to what is considered the right diet/food to eat.

  • Reply
    Katherine Jones
    16th February 2016 at 3:49 am

    This is very powerful Eunice – how ridiculous is it to reject the experiences and observations of the individual as evidence when it is in fact the basis of any collection of ‘evidence’ that we use? Unfortunately we have lost what true research is all about – and how to use the evidence of the individual experience in a meaningful way. I love how you have brought it all back to the foundations again.

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