Posted By Philip McAleenan
Andy,
Your conclusion that we should abandon risk assessment does not follow logically from what I have stated. In fact my posting made no reference to risk assessment, which is a tool to determine what control measures are necessary for the elimination of risk. I raised issues pertaining to “risk” itself, i.e. the probability of a hazardous event occurring. To conflate the two, as you did, is either disingenuous or, as your final paragraph illustrates, the result of a misunderstanding of my point.
Risk, as in the probability of an undesirable event occurring, is the outcome of a series of cause and effect events that lead inevitably to the undesirable event. This is the case when the probability is 1:1. It will always result in the undesirable event.
When the probability is less than 1:1, e.g. 1:2, it means that there is more than one possible outcome from the process of cause and effect. But, if we know every cause and its effect, then there can logically be only one outcome. How then can there be more than one after the initiating event or cause?
The answer lies in the fact that all the causes and effects of the process are not known and therefore not controlled. If we throw a die and want a six, the probability is 1:6. Why? It is not simply because there are six possible outcomes, we can always get a six if we control the process correctly, e.g. by simply setting the die on the table six facing up. But because we cast the die, it is out of our control once it leaves our hand and any one of the six faces will land up.
So too with work events; if we have assessed the process and calculated that there is a 1:x probability of an accident occurring, then in effect we are stating that there is more than one possible outcome to the work process. If we only want one outcome and there are multiple possible outcomes, then somewhere along the way we have lost control. And if we have lost control, the accident will occur at any time.
Risk assessment s only one of many tools that we use to ensure that we fully understand and control our work processes. The above analysis does not negate that use of such a tool. In fact a proper understanding of “risk” will allow the assessor to be more effective in using risk assessment.
Two final points; in reference to the asteroid, in the apparent random chaos of the universe we have no control over such events in our day-to-day activities. But when work demands that we have control, such as sending vehicles and people into space, then we had better make sure that we do gain the necessary control to offer protection.
Secondly, the statistical probability that some thing will never happen is 0. With any other figure, it may never happen, but again it may happen next time. And those who do not understand that …
Philip