Sunday, December 15, 2013

Safety critical principles


At Critical Uncertainties there is a very good posting of some 21 principles attendant to managing risk and providing for safety in systems where safety criticality is predominant.

Here are a few I picked out that seem to come up often when doing a risk register of unlikely but severe risk events and outcomes.

I add this bit of editorial: the principles lead directly to the so-called "1% Doctrine" that posits that peremptory action is justified to neutralize a risk source, not just mitigate consequences.

The 1% Doctrine is Principle 1 in different words. 

We see this played out in the security arena big time, everything from preempting WMD to preempting travellers at the airport check-points.

But on the project scale we see peremptory action to avoid a project budget cut or resource reassignment. In other words these principles have both strategic and tactical application:

  1. Where risk exists there also exists an ethical duty of decision makers to eliminate if practical or, if it is not, to reduce such risks to an acceptable level.
  2. The greater the potential severity of loss associated with the system the more likely the organisational and societal focus will be on prevention ... rather than mitigation of consequences.
  3. Risk ... is a social construct and can never be evaluated in a totally objective fashion.
  4. Some unknown risks may disclose themselves in the life of the systems, some may never be identified.
  5. The greater the severity of a [risk] the lower the required occurrence rate and the greater the .... uncertainty of estimation of probability.
  6. The greater the .....uncertainty of probability estimates the more the focus should be upon the reduction in the severity of consequences.
  7. The more complex a system the more likely it is that an accident will be due to the unintended and unidentified interaction of components, rather than singular component failures or human errors.
  8. One can never absolutely ‘prove’ the safety of a system as such arguments are inherently inductive.


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