Tag Archives: safety

Systems Thinking, Complexity, and Root Cause

I'm getting so very tired of safety/accident researchers claiming that root cause analysis is an invalid, blame-focused practice that ignores systems and complexity. Most root cause investigators that I know are pretty well oriented towards process, organization, and system issues as the fundamental sources underlying problems and accidents... and even some of our simplest analysis tools (e.g., TWIN) include specific checks for complex-system characteristics/behaviours (e.g., hidden system responses, separation between cause and effect).

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The Fortunate Near-Miss Event

What do you consider to be an event worthy of investigation? Do you look only at events that had serious consequences, or do you consider less serious events as well? What about near-misses?

I've recently been involved in the investigation of a near-miss event. By near-miss (or near-hit?), I mean an event that almost happened -- an event that terminated one step before a serious consequence was experienced. As is often the case, the event sequence was a seeming string of coincidences. It ended without consequence simply because there was nobody at the event location to be injured.
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Event Frequency and Severity

In 1931, HW Heinrich published his findings from a review of hundreds of thousands of safety incidents. His data showed that on average, for every 300 near-miss events without injury, there would be 29 minor to moderate injuries and 1 major injury or fatality. Similar studies done since 1931 have yielded similar results. The data is deceptively, compellingly simple -- the meaning, however, is not. What is implied by a 300:29:1 ratio of near-misses to moderate injuries to major injuries? Why do we care? Is there some deeper, underlying pattern to this data?
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