Despite all our best intentions, accidents happen. Analysis of accidents in large complex systems such as power stations or plane crashes led to an understanding that "no one failure, human or technical, is sufficient to cause an accident. Rather, it involves the unlikely and often unforeseeable conjunction of several contributing factors arising from different levels of the system."

James Reason's Swiss Cheese Model is a memorable visual metaphor that illustrates how each safeguard may contain a latent flaw, or hole, and that an unfortunate circumstance, may result in these holes lining up to disastrous effect. It's also a nice reminder that multiple layers of defence will be more effective, but even with our best efforts, there's still potential for something to go wrong.

Excerpt from Revisiting the "Swiss Cheese" Model of Accidents (pdf), Reason, Hollnagel and Paries, 2006.

Coronavirus example from the Cleveland Clinic.

The Swiss Cheese Model

How small changes in customer demand can produce considerable disruption upstream in the supply chain. For instance, a sudden surge in the buying of toilet paper may cause retailers to put in larger orders to make sure they can keep up with demand. Manufacturers, in turn, may put in even larger orders for raw materials to make sure they don’t get caught out. In the meantime, customers had bought all the toilet paper they ever needed and demand suddenly dropped causing retailers to cancel all their orders, manufacturers to halt production and suppliers to be left with big stockpiles of unwanted raw materials.

I learned about the bullwhip effect from Tomas Tunguz where he considers economic effects of the coronavirus. He explains it with a brewery example in his article on proxy metrics for startups.

Sketchplanations tagged with coronavirus