Safety Metrics

Recent developments promising to make possible the objective assessment of accident prevention performance have stimulated my adrenaline. The development emerged from dialogues with my co-author of a paper presented at an ISASI Seminar in September 2009, during our development of our presentation for the Seminar. The concept is based on the use of "behavior sets" generated during accidents, incidents or other experiences with undesired outcomes, and the use of those behavior sets in future investigations, ongoing activities and new systems analyses.

No two accidents are identical. However, some interactions during an accident may be similar or identical to those experienced in previous accidents. The similarities can be found by analyzing the interactions as behavior sets - or interactions among the people, objects and energies involved. In future investigations, the presence of a previously experienced (and reported) behavior set indicates the accident is a "retrocursor" accident, or one with precedents which should not have been repeated - e.g., should have been prevented. Such presence offers a retrospective assessment of the lessons learned practices designed to prevent accident recurrence, or retrospective prevention performance measurement.

Behavior sets offer opportunities for examining ongoing operations to find the same or similar patterns of behavioral interactions in those operations, and if found, to change those behaviors and reduce the risk of future accidents. That's prospective accident prevention action, measured by the discovery and modification of risk raising behavior patterns. They also offer unambiguous operations audit check-off items, and guidance for change analysts and procedures developers and reviewers.

A third prevention opportunity is to review planned operations during design stages to determine whether they might contain planned or potential interactions identified in previous accidents. Their presence or absence in future operations then offers a measure of the effectiveness of the predictive analyses in preventing future accidents. I see the availability of behavior sets having a significant impact on future risk assessments, because the offer an unambiguous multi-dimensional definition of risk raisers at the lowest level of abstraction, as contrasted with the uni-dimensional nature of a factor, error, failure, hazard or cause of any kind.

When combined with the input-output data structure suggested in a 2007 paper, it seems to me that it's worth pursuing.

The ideas were first proposed in our ISASI paper and presentation that can be found at

http://www.iprr.org/research/llprojcontents.html, items 9-11.