Understanding Risk Ratings

You have referenced a Risk Assessment from the Risk Assessment module. The document contains information about hazards control measures and risk ratings. This article explains how to interpret the risk ratings.

  • Risk Assessments contain a list hazards which are associated with the subject of the Risk Assessment. For example, a Risk Assessment about "Use of Chain Saws" will list hazards such as; flying debris, manual handling and contact with moving parts.
  • The hazard is rated in two ways.
    • First, the 'Severity' of the injury is rated from 1 to 10 where 1 is a very minor injury and 10 is a fatality.
    • Second, the 'Likelihood' of encountering the hazard is rated from 1 to 10. Where 1 means very unlikely and 10 means unavoidable.
  • The risk rating for each hazard is calculated by multiplying the Severity by the Likelihood to get a score between 1 and 100. 
    • In this example, the highest risk rating is "Contact with Moving Parts" with a Severity of 9 and a Likelihood of 7.   So the Risk Rating is 9 x 7 = 63.
  • The Risk Rating is displayed on the Risk Assessment as 'Before Control Measures'. This is the Risk Rating before any control measures are put in place to manage the risk.
  • Note that the calculation from "Contact with Moving Parts" is displayed below the Risk Rating number.
  • Risk Assessments also contain Control Measures.
    • Control Measures are things which can be applied to reduce the likelihood of encountering the hazards, such; providing proper training, wearing personal protective equipment and having proper first aid training.


  • The reduced Likelihoods are displayed in green (above).
  • The Risk Assessment displays a reduced Risk Rating for 'After Control Measures' have been applied.
  • Note the calculation is now based on "Hand/Arm Vibration" because this combination of severity and likelihood now gives the highest Risk Rating.