Monday, March 17, 2014

Moving towards Safety-II: ensuring thing go right

High lights from an article in The Ergonomist March 2014 by Steven Shorrock and Tony Licu.  A far more in-depth 'White paper' is available from

It has been suggested that safety management should move from ensuring that "as few things as possible go wrong" to ensuring that "as many things as possible go right."  This is being described as a move from Safety-I to Safety-II.

One of the main reasons for this change is the massive developments in technology over the last couple of decades.  You just have to look at what you can do on an iPad now compared to computers of the past.  The impact has been increased demand on systems leading to more complexity.  The rate of change is rapid, and the reality is that thinking on safety and the causes of accidents is not keeping up.

The complexity and connectivity of modern systems means it is impossible to fully understand how they work or predict how they can failure.  One outcome of this is that the human factor remains important as people have to be flexible to adjust to changes in demand and conditions.

Safety-II focusses more on the fact that things go right most of the time, whilst acknowledging they can still go wrong.  It requires us to understand how systems made up of technical and human resources really work in practice.  This means we need to understand how people, procedures and equipment interact, and the variability in these in these interactions.  This will allow us to anticipate developments proactively and understand how things occasionally go wrong.

One outcome from a move to Safety-II is that we have to stop saying that accidents occur due to 'human error.'  People are having to constantly adjust their performance constantly (think about driving a car) and most of the time they do this brilliantly.  But sometimes things do not perform as expected (this includes the human element) and this can result in an accident.  If we really want to improve safety we have to understand all the variations that the system (technical and human) deals with, and not just the ones where it fails.  If there is an accident our investigation should start with developing an understanding of how things normally work and not just the isolated case of where it has gone wrong.