Category Archives: anecdotal evidence

Burden of Proof in Healthcare

The burden of proof lies with she who asserts a positive.

One cannot prove the null hypothesis.


With people, the null hypothesis is that we’re innocent. Therefore, people are innocent until proven guilty.

With interventions/therapies/treatments/medicines/surgeries, the null hypothesis is that they’re ineffective and/or unsafe. Therefore, interventions/therapies/treatments/medicines/surgeries are to be treated as ineffective and/or unsafe until proven sufficiently effective and/or safe for public consumption.


For people, that’s why we have a right to a trial before being legally punished.

For interventions/therapies/treatments/medicines/surgeries, that’s why we have scientific randomized controlled clinical trials (which have to be carefully designed, replicable, and use proper active control groups that control for differing expectations, etc.) before recommending wider public use.


In law, anecdotal “evidence” is inadmissible as it is not reliable enough to carry the weight needed to overcome the null hypothesis of innocence and to prove a person guilty.

In science and healthcare, anecdotal “evidence” is similarly inadmissible as it does not meet the experimental standards required to overcome the null hypothesis of ineffective and/or unsafe, and to show that an intervention/therapy/treatment/medicine/surgery is effective and/or safe.


If we are to take ‘first do no harm’ seriously, then interventions that don’t meet these scientific standards should not be tried out on the public — at least not without prior transparent disclosures of their experimental, unsubstantiated, and potentially harmful nature. And, in the unfortunate event that this condition is not met, as soon as we hear of cases in which someone may be harmed, we have a further and more urgent reason to pull the intervention off the market. In the absence of properly controlled rigorous scientific evidence in favor of an intervention, there is insufficient justification to press on with it. If there are people claiming that such an intervention has harmed them, then they ought to be heeded — there’s insufficient valid scientific evidence to justify it; anecdotal evidence in favor of it  doesn’t cut it in the face of people getting hurt. It’s not okay for us to look the other way, ignore the burden of proof, and leave human collateral damage behind.

In a nutshell, the null hypothesis is the default condition, and anecdotes/testimonials do not meet the burden of proof to overcome it. Rather, we need legal trials to show that a person is guilty and properly controlled scientific trials to show that a treatment is effective and/or safe. In the absence of this legally or scientifically admissible evidence, punishing a person or providing a treatment is unjustified, potentially harmful, and ought to be discontinued (or transparently acknowledged to be a risky endeavor).

Further Reading/Viewing:

Video: The Burden of Proof    [highly rated]
http://www.youtube.com/watch?v=KayBys8gaJY

Wikipedia: Philosophic Burden of Proof
http://en.wikipedia.org/wiki/Philosophic_burden_of_proof

The Burden of Proof
http://www.qcc.cuny.edu/socialsciences/ppecorino/phil_of_religion_text/CHAPTER_5_ARGUMENTS_EXPERIENCE/Burden-of-Proof.htm

Burden of Proof
http://www.nizkor.org/features/fallacies/burden-of-proof.html

Wikipedia: Anecdotal Evidence
http://en.wikipedia.org/wiki/Anecdotal_evidence

The Role of Anecdotes in Science-Based Medicine
http://www.sciencebasedmedicine.org/the-role-of-anecdotes-in-science-based-medicine/

Anecdotes, testimonials and urban legends
http://scienceornot.net/2012/03/14/anecdotes-testimonials-and-urban-legends/

Levels of Evidence
http://www.cebm.net/?o=1025

Wikipedia: Pseudoscience
http://en.wikipedia.org/wiki/Pseudoscience

Distinguishing Pseudoscience and Science
https://docs.google.com/document/d/1Rw98m-co18a57j8DKpVvqSCQdEkiafaKYO9KVsBBwk4/edit?pli=1

Quackery: Why Bogus Therapies Often Seem to Work
http://www.quackwatch.com/01QuackeryRelatedTopics/altbelief.html

Quackery: Why Bogus Therapies Seem to Work
http://www.csicop.org/si/show/why_bogus_therapies_seem_to_work/

Pop Quiz – What can we learn from an intervention study?
http://blog.dansimons.com/2013/07/pop-quiz-what-can-we-learn-from.html

Logical Fallacy: Bandwagon
https://yourlogicalfallacyis.com/bandwagon

Examples of what can happen when the burden of proof is ignored:

Snake oil, bloodletting, lobotomies …
http://science.howstuffworks.com/life/human-biology/medical-quackery.htm#page=0

Psychotherapies that increase trauma …
http://mindhacks.com/2011/09/10/escaping-from-the-past-of-disaster-psychology/
http://www.psychologytoday.com/blog/the-open-mind/201001/when-counseling-is-dangerous-0

The Death and Afterlife of Thalidomide
http://www.nytimes.com/2013/09/23/booming/the-death-and-afterlife-of-thalidomide.html

What’s the harm?
368,379 people killed, 306,096 injured and over $2,815,931,000 in economic damages 
http://whatstheharm.net/

Do you have an example of what can happen when the burden of proof is ignored? Please feel free to contact me or leave a comment with a brief description of how your example demonstrates the hazards of ignoring the burden of proof. Thank you!