Risk

Risk is never only a severity or only a likelihood; both have to be estimated for each hazardous situation. Many weaknesses in risk files come from mixing up hazard, hazardous situation and risk.

‘risk’ means the combination of the probability of occurrence of harm and the severity of that harm;

EU MDR, Article 2(23)

‘risk’ means the combination of the probability of occurrence of harm and the severity of that harm;

IVDR, Article 2(16)

combination of the probability of occurrence of harm (3.3) and the severity (3.27) of that harm (3.3) [SOURCE: ISO/IEC Guide 63:2019, 3.10, modified — Note 1 to entry deleted.]

ISO 14971:2019, clause 3.18

combination of the probability of occurrence of HARM and the severity of that HARM Note 1 to entry: The probability of occurrence includes the exposure to a HAZARDOUS SITUATION and the possibility to avoid or limit the HARM [SOURCE: ISO/IEC Guide 51:2014, 3.9, modified – Note 1 to entry updated to remove the reference to hazardous event.]

IEC 82304-1:2016, clause 3.13

combination of the probability of occurrence of HARM and the severity of that HARM [ISO 14971:2007, 2.16]

IEC 62304:2006+AMD1:2015, clause 3.16

combination of the probability of occurrence of harm and the severity of that harm [SOURCE: ISO 14971:2019,[8] 3.18]

ISO 15223-1:2021, clause 3.14

effect of uncertainty Note 1 to entry: An effect is a deviation from the expected – positive or negative. Note 2 to entry: Uncertainty is the state, even partial, of deficiency of information related to, understanding or knowledge of, an event, its consequence and likelihood. Note 3 to entry: Risk is often characterized by reference to potential events (as defined in ISO Guide 73:2009, 3.5.1.3) and consequences (as defined in ISO Guide 73:2009, 3.6.1.3), or a combination of these. Note 4 to entry: Risk is often expressed in terms of a combination of the consequences of an event (including changes in circumstances) and the associated likelihood (as defined in ISO Guide 73:2009, 3.6.1.1) of occurrence. [SOURCE: ISO 9000:2015, 3.7.9, modified — Notes to entry 5 and 6 have been deleted]

ISO 19011:2018, clause 3.19

combination of the probability of occurrence of harm and the severity of that harm Note 1 to entry: This definition of “risk” differs from the definition given in ISO 9000:2015. [SOURCE: ISO 14971:2007, 2.16]

ISO 13485:2016, clause 3.17

The combination of the probability of occurrence of harm and the severity of that harm. For the purposes of this guidance, may relate to either safety or effectiveness (e.g., risk of decreasing device effectiveness).

FDA guidance: Deciding When to Submit a 510(k) for a Change to an Existing Device (October 2017), Appendix C, Significant Terminology

The MDR, the IVDR and the FDA guidance share the same core wording. The FDA 510(k) change guidance adds that, for its purposes, risk may relate to effectiveness as well as safety, such as a risk of reduced device effectiveness.