In our last blog, we briefly mentioned ISO 31000 guidelines on risk analysis and then introduced the bowtie methodology.
In this week’s blog, we will explore this in more detail using the bowtie methodology.
According to the ISO 31000 guideline, you should consider multiple factors during the risk analysis phase. As the International Organization of Standardization states:
“Risk analysis should consider factors such as”:
1 – The likelihood of events and consequences
Although the bowtie method is more qualitative at its core, it is also possible to add quantitative data to its different elements. Indeed, there are instances of people combining the LOPA technique with the bowtie methodology to great success.
In addition, it is also possible to display risk matrices (see figure 1) on consequences or even on the hazard or top event to capture the likelihood of certain events. Likelihood alone, however, is not enough to properly assign the risk, you will also need…
2 – The nature and magnitude of consequences
Once the likelihood has been verified, it needs to be calculated together with the severity, or magnitude of an event. In this way, the impact of the event of the consequence can be assessed, as a result prioritizing which consequence is most dangerous becomes clearer. This will make ALARP analyses easier thus allowing decision makers to make better-informed decisions.