The ISO 14971, the standard for risk management for medical devices, defines the term severity (damage) as a "measure of the potential impact of a hazard".
The risk acceptance matrix serves manufacturers in assessing the risks based on the probability and severity of damage. This assumes that probabilities and severities are thus divisible and able to be ever quantified in classes.
The challenge facing many medical products manufacturers, is that it is not easy to quantify the severity of damage. It requires a sharp classification feature to precisely classify damage so it is reproducible for a severity.
Examples of classification characteristics of damage
When studying the MEDDEV 2:12. I came across a definition of serious damage:
It might help in formulating the severity of your classes.
Another classification of (short-term) damages can be found in Wikipedia (NACA score). This classification originates from the National Advisory Committee for Aeronautics - originally developed for the classification of accidents in aviation.
The evaluation of this severity is difficult:
Many scores only consider the severity of acute injuries. A non-life-threatening but non reversible damage such as a permanent disability can be classified as not good in this scheme. So this does not help us in the ethical debate about whether one should use the maximum short-term effect ("the level of the injury curve"), or instead the duration of the effect, or rather the "Integral" of this curve in the damage.
Tips for defining the severity classes
In the auditgarant you will learn step by step, and very concretely, how you can define the severity of damage in your risk assessment matrix. You can check on the basis of several examples, if you can identify and correct faulty definitions.