Medicine in small doses

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‘How often have you been over optimistic about the time taken to complete a task, particularly in the operating theatre, much to the chagrin of the theatre staff and your anaesthetist, when in fact it has taken much longer than you expected?’
Well you are not alone, and the anaesthetists are not necessary the role model when it comes to estimating time.
This concept of ‘task time optimism’ is referred to as ‘the planning fallacy’ which was first proposed by Daniel Kahneman and Amos Tversky (TIMS, Studies in Management Science 1979; 12: 313–7) and expanded in Kahneman's best seller Thinking Fast and Slow (Penguin Group: London, 2011).
It is a phenomenon in which predictions about how much time will be needed to complete a future task display an optimism bias and underestimates the time needed.
The often quoted example of the planning fallacy regards the construction of the Sydney Opera House, which was expected to be completed in 1963 and a scaled‐down version opened in 1973, a decade later, the original cost being estimated at $7 million, whereas the delayed completion led to a cost of over $102 million (
The planning fallacy occurs regardless of the individual's knowledge that past tasks of a similar nature have taken longer to complete than generally planned. The bias only affects predictions about one's own tasks; when outside observers predict task completion times they show a pessimistic bias, overestimating the time needed. Does this sound familiar? The charge nurse in the operating theatre being pessimistic about how long you might take to perform a procedure?
A modification to the planning fallacy was suggested by Lovallo and Kahneman (Harvard Business Review 2003; July: 56–63), in which they proposed an expanded definition as a tendency to underestimate the time, cost and tasks of future actions and at the same time overestimate the benefits of the same actions, leading not only to time overruns, but also cost overruns and benefit shortfalls.
Some explanations for the planning fallacy include: planners focusing on the most optimist scenario for the task rather than using their full experience of how much time similar tasks require – the concept of wishful thinking – in which people think tasks will be finished quickly and easily because that is what they want to be the case or people do not correctly recall the amount of time that similar tasks have taken in the past.
So how can we mitigate against the planning fallacy? The obvious answer is time management, but importantly, having the insight to know that planning fallacy is problem and fixing it. Flyvbjerg (Project Management Journal 2006; 37: 5–15) proposed to frame the forecasting problem by utilizing all the distribution information available called reference class forecasting which can be implemented in four phases: (i) identify the reference class (the operating theatre); (ii) obtain the statistics (average time for the case); (iii) generate a baseline prediction (estimated time for the case); and (iv) adjust the prediction by other mitigating factors (patient risk factors).
So, are surgeons guilty of the planning fallacy?
In the time‐out component of the WHO Surgical Safety Checklist, introduced in 2008 ( the surgeon is asked to predict how long the operation is likely to last. This was referred to by Travis et al. (BMJ 2014; 349: g7182. in this single centre prospective observational study from the Waikato Hospital, Hamilton, New Zealand, involving 92 operating theatre staff who were asked how long they thought their procedure would take. General surgeons underestimated the time require for the procedures by 31 min, plastic surgeons by 5 min, and orthopaedic surgeons by 1 min. Whereas anaesthetists underestimated the time taken by 35 min.
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