Westminster Risk Register

All risks are scored on impact and likelihood which produces an Overall Risk Rating. Various factors influence the assessment of impact and likelihood such as demographics, transportation, and environmental elements.

These factors can influence and inform how a particular risk would pan out in a specific geographical area.

Impact

For impact, a rating is developed by looking at various impact categories, which are different elements in a community that may be impacted such as:

• human welfare
• behavioural impacts
• the economy
• any essential services
• the environment
• security

Categories are then split into several “indicators” which are each scored. Indicator scores are then combined to reach a score for each category, and lastly the category scores are combined to reach an overall impact score.

The overall impact score is on a scale of 1, low impact, to 5, catastrophic impact. 

Likelihood

Likelihood is assessed on a scale of 1, low probability of occurring, to 5, high probability of occurring.

The likelihood scale is based on the probability of the Reasonable Worst-Case Scenario (RWCS) occurring in a 12-month period.

The RWCS is informed by:

• historical and scientific data
• modelling
• professional expert judgement of both the likelihood and impact of a risk
• government guidance
• research
• local knowledge

Overall risk rating

Once an overall risk rating is achieved, the risks are placed into four key categories. They range from Very High, High, Medium, and Low. Each category is defined by using a nationally approved definition.

The Westminster Risk Register provides the full definition of each category.