Black swans and fat tails in medicine
In medicine, we also have a strong aversion to risk and therefore often implement systems that include, for example, checklists to minimise the risk of adverse events (2). However, unlikely black swan events also occur in medicine, where they can have an enormous impact. We therefore seek to guard against them.
Fat tails are essential for most investment decisions in the health services, associated with localisation, structural design, capacity, reserves, specialisation and skills. Fat tails mean that extreme outcomes are more likely. To avoid disastrous consequences, it might therefore be sensible and rational to build up spare capacity to handle relevant extreme outcomes. As a rule, the best possible decisions made under circumstances of such real uncertainty produce 'cost efficiency through necessary overcapacity' as a result. This is the only way to achieve a minimum standard in healthcare provision at the lowest possible cost.
Structural uncertainty requires us to take better account of unlikely events that may occur
In a complex hospital setting with acutely ill patients or sudden catastrophic events during surgery, time is short and the information is often limited and incomplete (3). Our approach to black swan events is crucial for the way in which we organise ourselves and for how we interpret uncommon events and their consequences. After a black swan event, evidence of how this event could have been predicted and averted is often collected. Often, this is a misguided approach. Adverse events occur because they are neither easy to predict, nor easy to prevent. Structural uncertainty requires us to take better account of unlikely events that may occur in our daily clinical work and when major changes to the health services are being planned.
Taleb argues that the future will be more uncertain and even harder to predict, even though our total knowledge is increasing (1). Perhaps a heightened awareness of black swans and fat tails could help us encounter future challenges in medicine? It is crucial that decision-makers share the uncertainty in their decisions with the community and do not behave like armchair generals. By doing so, their decisions are likely to be less fraught with risk (4). The ongoing COVID-19 pandemic provides a good illustration of how a black swan event (it is debatable whether the pandemic is a black swan) can change the rules of the game in society, and of how difficult it is to predict when and with what effect such an event will occur (5).
In discussions on the construction and location of hospitals, and the organisation of health trusts, it is important that we recognise that black swan events occur with unpredictable regularity. Nor can we predict how and how much such events will affect us – perhaps more than we want. We would therefore do well to acknowledge their existence when we make strategic decisions in the health services.