Not specifically replying to anybody, but as a general reflection on various posts in this thread, I'd like to suggest a different approach.
Originally, as much as I got, the issue was "How do you verify the effectiveness of a preventive action?". A PA is directed at eliminating a root cause of an undesirable happening that has not occured yet (otherwise it's a CA). So, it's effectiveness should be measured by the removal of that specific defined root cause, not by the prevention of the undesirable happening.
If we accept that approach, it does become quite a simple issue. We simply check whether that pin-pointed thing we set off to eliminate was actually eliminated. To go back to the railing example - the undesirable happening was falling over the edge. A root casue (not THE root casue, because there are more than one) is the lack of a physical barrier accross the edge. PA: installation of a railing. Was the root cause we set off to eliminate actually eliminated? Yes. So that particular PA was effective.
Cheers,
Ronen.
Originally, as much as I got, the issue was "How do you verify the effectiveness of a preventive action?". A PA is directed at eliminating a root cause of an undesirable happening that has not occured yet (otherwise it's a CA). So, it's effectiveness should be measured by the removal of that specific defined root cause, not by the prevention of the undesirable happening.
If we accept that approach, it does become quite a simple issue. We simply check whether that pin-pointed thing we set off to eliminate was actually eliminated. To go back to the railing example - the undesirable happening was falling over the edge. A root casue (not THE root casue, because there are more than one) is the lack of a physical barrier accross the edge. PA: installation of a railing. Was the root cause we set off to eliminate actually eliminated? Yes. So that particular PA was effective.
Cheers,
Ronen.
