Nearly 40 years ago the New England Journal of Medicine published a short survey of doctors’ understanding of the results of diagnostic tests.1 The participants, all doctors or medical students at Harvard teaching hospitals, were asked, “If a test to detect a disease whose prevalence is 1/1000 has a false positive rate of 5%, what is the chance that a person found to have a positive result actually has the disease, assuming that you know nothing else about the person’s symptoms or signs?” This wasn’t a very difficult question, which made the results all the more shocking. Fewer than a fifth of participants gave the correct answer, and most thought that the hypothetical patient had a 95% chance of having the disease.
Of course, this was a long time ago, and medical curriculums now contain much more in the way of statistics and probabilistic reasoning. You might expect that if the exercise were repeated today almost everyone would give the right answer. But you’d …
For doctors with an interest in explaining risk to patients in meaningful ways and terms/language try David Spiegelhalter’s Personal Home Page. David is Winton Professor for the Public Understanding of Risk at the University of Cambridge and has been in post since 2007. In The Information Age patients will need better and better explanations..
Understanding Uncertainty and Risk I work with a small team comprising Mike Pearson (web and animation), and Owen Smith (web). Our work focuses on the appropriate use of quantitative methods in dealing with risk and uncertainty in the lives of individuals and society. We fall into the broad category of ‘public understanding of science’, while our work with schools can be considered as ‘maths outreach’. However we try to take a view of the subject that extends beyond the application of probability and statistics, acknowledging that there are deeper uncertainties that cannot be easily put into a formal framework, and that social and psychological issues necessarily play a vital role. We are involved in a number of different areas: Website: Understanding Uncertainty
- This is an educational resource featuring the use of probability and statistics in everyday life, and makes extensive use of animations to help ‘tell the story’ of the data. Googling ‘Uncertainty’ should find it. The Cambridge Coincidence Collection started as part of filming for theBBC4 programme, but since then over 3300 coincidences have been contributed to our website.Don’t get confused with The Institute of Risk Management (IRM) which is something completely different in the finance industry.
Perhaps the strategists should have thought about financial risk when they mooted devolution, and ignored the “frontier issues” which Aneurin Bevan warned about in “In place of fear”.
University of Edinburgh cardiovascular risk calculator – which leads to different graphical expositions.