Archives For Uncertainty

Interesting article on old school rail safety and lessons for the modern nuclear industry. As a somewhat ironic addendum the early nuclear industry safety studies also overlooked the risks posed by large inventories of fuel rods on site, the then assumption being that they’d be shipped off to a reprocessing facility as soon as possible, it’s hard to predict the future. :)

Enshrined in Australia’s current workplace health and safety legislation is the principle of ‘So Far As Is Reasonably Practical’. In essence SFAIRP requires you to eliminate or to reduce risk to a negligible level as is (surprise) reasonably practical. While there’s been a lot of commentary on the increased requirements for diligence (read industry moaning and groaning) there’s been little or no consideration of what is the ‘theory of risk’ that backs this legislative principle and how it shapes the current legislation, let alone whether for good or ill. So I thought I’d take a stab at it. :) Continue Reading…

NASA safety handbook cover

Way, way back in 2011 NASA published the first volume of their planned two volume epic on system safety titled strangely enough “NASA System Safety Handbook Volume 1, System Safety Framework and Concepts for Implementation“, catchy eh?

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Process is no substitute for paying attention

As Weick has pointed out, to manage the unexpected we need to be reliably mindful, not reliably mindless. Obvious as that truism may be, those who invest heavily in plans, procedures, process and policy also end up perpetuating and reinforcing a whole raft of expectations, and thus investing in an organisational culture of mindlessness rather than mindfulness.

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An articulated guess beats an unspoken assumption

Frederick Brooks

A point that Fred Brooks makes in his recent work the Design of Design is that it’s wiser to explicitly make specific assumptions, even if that entails guessing the values, rather than leave the assumption un-stated and vague because ‘we just don’t know’. Brooks notes that while specific and explicit assumptions may be questioned, implicit and vague ones definitely won’t be. If a critical aspect of your design rests upon such fuzzy unarticulated assumptions, then the results can be dire.

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While I’m on the subject of visualising risk the Understanding Uncertainty site run by the University of Cambridge’s Winton Group gives some good examples of how visualisation techniques can present risk.

In June of 2011 the Australian Safety Critical Systems Association (ASCSA) published a short discussion paper on what they believed to be the philosophical principles necessary to successfully guide the development of a safety critical system. The paper identified eight management and eight technical principles, but do these principles do justice to the purported purpose of the paper?

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