2.3. Rate the risk in terms of determining the likelihood and the impact of
the risk occurring.
Risk is measured in terms of likelihood and impact i.e. the likelihood of an event
occurring combined with its impact (consequence). The methodology for measuring
risk in this way plots a single ascribed value of likelihood against a single ascribed
value of impact and therefore reduces risk to a single, easily comparable value.
This process, except in the relatively rare case where statistical data are available,
uses informed but subjective judgement in assigning the values for likelihood and
impact. If different risks are to be compared across the HSE, it is necessary to
minimise the variation in the judgement applied to the values of likelihood and
impact assigned to a risk. This requires the adoption of a HSE-wide, standardised
approach to the assignment of likelihood and impact.
Rare/Remote (1) Unlikely (2) Possible (3) Likely (4) Almost Certain (5)
Two elements are determined when assessing the level of risk posed by the risk that
has been identified;
(i) The likelihood that a risk may occur or reoccur.
(ii) The impact of harm to service users, staff, services, environment or the
organisation.