Models in safety thinking take different shapes and forms. A conversation might start – what’s a model? Why are they useful?
Here’s a go at an answer. It’s always risky to explain why something works. It can be like a dry analysis of the particulars of a good joke. That kills the essence. As the words attributed to Albert Einstein say: if you can’t explain it simply then you don’t understand it well enough. Even if that’s not literally a quote it sums-up the need for simplicity.
Aviation is a highly complex, interconnected, socio-technical system with a legacy that coexists with rapid advancement. There are few parts of the globe that are not touched by aviation in some way or another. Getting to and from Arctic wastes, commuting between vast cities or traversing the widest oceans. Aviation touches all of them every day.
There is no piece of paper big enough to write a detailed description of every part of the worldwide aviation system. Even the most extensive computer simulations just take on a small part of the whole. I often use this phrase – “it’s more than a head full”. What I mean is that however smart we might think we are, the normal person can only comprehend a slice of what’s happening. A slice frozen in time.
We get over our limitations in perception and understanding but approximating. That is to carve out a “model” of what’s happening and how parts of a complex system interact. That sounds easy enough to construct. It’s a lot harder than first might be thought.
For one, a model needs to be sufficiently universal to capture an underlying reality or theme.
Next, a model needs to be useful. It has utility. It’s proven to work. To produce useful outcomes.
Thirdly, a model needs to communicate a message across cultures, beliefs and disciplines.
A model that meets all the needs described above can be as big an advancement as any hard technology. I guess it’s not surprising that a professor of psychology comes up with one that has been used and reused successfully over decades.
This week has seen the passing of Professor James T. Reason. He’s left us with a legacy that’s almost incomparable. His Swiss cheese model[1] has become a basic part of every aviation safety professional’s training.
I’ve debated and discussed accident causation a lot. The Swiss cheese model[2] is not the only way of thinking about how accidents happen, but it is an extremely good one. It promotes a way of thinking about how to defend against accidents. That’s powerful.
Like all models it’s a simplification of a highly complex system. Its great strength is that this model allows us to see through the mist. To see part of what is obscured by complexity. That is immensely valuable.
Thank you, Professor Reason.
NOTE: An IFA Video with Professor Reason Every Day – 20 min film – International Federation of Airworthiness.
[1] https://en.wikipedia.org/wiki/Swiss_cheese_model
[2] https://www.eurocontrol.int/sites/default/files/library/017_Swiss_Cheese_Model.pdf
John Vincent 