Statistics from Altmetric.com
Guiding parents through the diagnosis and management of rare and devastating conditions is difficult and draining. Perhaps the most tricky question to tackle is “why us?”. Most people are unable to assess probability and, even if they can understand how often in the population an event might occur, this rarely translates into an appreciation of the chances of such an event happening to them.1 The rarity of such an event makes it difficult to believe and make sense of why it has happened to any one individual. Having been a consultant paediatrician for ten months, I have found counselling parents facing these diagnoses one of the hardest aspects of my job. I am, however, getting a surprising amount of practice. Recent discussions in the medical and lay press, combined with a somewhat warped sense of fascination with probability and increasing disbelief relating to my experiences this year, led me to wonder if I am getting a predictable amount of practice, or if is this a highly unlikely sequence of events. I am part time, so carry about a tenth of the workload. Thus, I can calculate the probability that I might be the consultant responsible for any patient newly diagnosed with each condition in any one year in my district (table 1). If I am right, and each event is independent of the other, multiplying these probabilities together should give the probability of children with all of these conditions diagnosed in one year in Portsmouth being admitted under my care. This makes the probability of a paediatrician with a tenth of the workload in Portsmouth seeing all these conditions in one year, 6.1 × 10−16 or 1 in 1633 billion. We like to rely so much on measurement to help us make sense of what is happening in medicine. In this case, as the numbers get smaller (or bigger), they seem increasingly ridiculous. The reality of my caseload reminds me that this is really happening but the figures suggest it almost certainly isn't. I haven't spent too long wondering “why me?”. I have learned such a lot in this crash induction into consultant practice, perhaps most of all, the value of supportive colleagues. Of course for me the question “why?” doesn't intrude on my life and belief structure at all, but for parents it often remains the most difficult part to come to terms with. Knowing the chances of a rare event happening are no comfort once it has done so and the question being asked is “why?”. The author would like to thank those who checked her maths.
As a new consultant nearly 25 years ago, I came across a similar improbability list for GPs, written by the late Professor R S Illingworth. I used it in teaching for a decade or so, then lost the reference. Does anyone have it?