Uncertainty in medicine

I totally agree that uncertainty is not being addressed properly in medicine. It is important however to distinguish between uncertainty associated with non-transparent or intuitive thought and uncertainty associated with transparent reasoning [1]. 'Non-transparent thinking' is what we do quickly and intuitively but which is susceptible to error from psychological factors. 'Transparent reasoning' is how we check our intuitive conclusions and explain how we reason with uncertainty to patients, colleagues and examiners.

Transparent reasoning with uncertainty makes use of an important process that involves setting up lists of possibilities (e.g. differential diagnoses) and then trying to show that all but one are improbable [1]. This depends on showing that findings occur commonly in a suspected diagnosis, but less commonly in any diagnosis that we are trying to show to be improbable [2]. The same approach can be used to analyze clinical trials in a more transparent way to arrive at treatment indication criteria and cut-off points that avoid over-treatment and under-treatment [2, 3]. Mental checklists can also be used to try to show that sources of error and bias are improbable when interpreting published findings, including clinical trials [4]. This allows us to assess whether clinically significant findings are likely to be replicated.

All this is different from applying Bayes rule to sensitivities and false positive rates or simply applying tests of statistical significance alone. I think that it is failure to progress from the latter that is preventing uncertainty from being addresses properly in medicine.

References
1. Llewelyn H, Ang HA, Lewis K, Al-Abdullah A. Oxford Handbook of Clinical Diagnosis 3rd edition. Oxford University Press, 2014, pp 1 – 23. http://oxfordmedicine.com/view/10.1093/med/9780199679867.001.0001/med-97...
2. Llewelyn H, Ang HA, Lewis K, Al-Abdullah A. Oxford Handbook of Clinical Diagnosis 3rd edition. Oxford University Press 2014, pp 615 – 642. http://oxfordmedicine.com/view/10.1093/med/9780199679867.001.0001/med-97...
3. Llewelyn H. Reasoning in medicine and science. Oxford University Press blogs, 2103. https://blog.oup.com/2013/09/medical-diagnosis-reasoning-probable-elimin...
4. Llewelyn H. Reducing over -diagnosis and over-treatment by improving their criteria and stratifying them. Preventing Overdiagnosis Conference, Oxford, 2014, poster 34. http://www.preventingoverdiagnosis.net/2014presentations/Board%2034_Huw%...