The human factor – stress and fatigue in safety-relevant jobs

High-profile accidents such as Deepwater Horizon highlighted the role of the human factor in high-risk system vulnerability.1

Human failure as such goes back to inadequate working environments. Aspects of particular importance in this respect are (a) not maintained, insufficient or not functioning equipment; (b) unclear and faulty working procedures; (c) no or inadequate training of staff; (d) information overload; (e) insecurity of working staff due to large organisational changes.

The last point was proven in a study published in the Journal of Organizational Change Management looking at 253 losses triggered by human failure. 155 of them – or nearly 2 out of 3 – happened in companies that underwent large organisational changes two years prior to the event.2

Industries where the problem of human failure is very well investigated include aviation and hospitals. Several studies have shown again and again how the factors cited above contribute to pilots taking the wrong action in an environment that gave them no other choice.3 A tragic recent example was the Air France flight 447 from Rio to Paris in 2009. The French Civil Aviation Safety Investigation Authority's final report concluded that the aircraft crashed after temporary inconsistencies of the airspeed measurements, after which the crew reacted incorrectly and caused the aircraft to enter an aerodynamic stall from which it did not recover.4

The medical industry is also well investigated. In the US alone, 250 000 deaths per year are attributed to human error.5 Hospital staff are often not monitored for factors such as stress and exhaustion. Errors represent systemic problems, including poorly coordinated care, fragmented insurance networks, the absence or underuse of safety nets, and other protocols, in addition to unwarranted variation in physician practice patterns that lack accountability.

In summary, all research points to the fact that humans do not fail but their working environments do – by creating conditions where timely and appropriate reaction is impossible should an emergency arise.

The following list of important human factor elements is to be considered in identifying working environments that can lead to failure are the following : Lack of communication, distraction, lack of resources, stress, complacency, lack of teamwork, pressure, lack of awareness, lack of knowledge, fatigue, lack of assertiveness, norms and large scale reorganisation.

Potential impact:

  • Studies show that the human factor plays a crucial role in insured large scale industrial losses, both in terms of likelihood and impact.
  • As an example, some airlines have pushed for pilot payment according to actual flight hours. Compensation based on actual flight hours may lead to situations where pilots go to work even if they are not fit enough for flying an aircraft (e.g. due to illness)

This text is an excerpt from the "Swiss Re SONAR, New emerging risk insights", June 2017.


2 Mellert, et al (2015) "Examining the relationship between organizational change and financial loss", Journal of Organizational Change Management, 28: 1, 5971


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