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A railway company has established a risk acceptance criterion that states “The frequency of fatal accidents per year in our operation shall be less than 0.1 per year.” In this case, it is necessary to clarify if this applies only to employees or also to passengers and/or people crossing the railway line. The answer to this question affects the scope of the risk assessment.

If several types of assets are considered in the risk assessment, separate decision criteria need to be established for each type of asset. This may apply even if people are the only asset considered. Different criteria may, for example, be applied for employees and neighbors living close to a hazardous plant. Criteria for when the assets are considered to be harmed may also need to be established. Many risk assessments are concerned only with people, and the criteria for harm are then usually whether people are injured or not.

The risk assessment should demonstrate that all the significant accident scenarios related to each decision alternative have been considered. If only one decision alternative is considered, the risk assessment should cover the risk if the decision alternative is chosen and also the risk if the decision alternative is not chosen.

The role of the risk assessment in the decision‐making process is illustrated in Figure 3.4 . From the decisions, the required input can be defined, and this determines the objectives and scope of the risk assessment. When the assessment is completed and results are ready, this feeds back to the decisions again, together with other relevant information that is taken into account (e.g. feasibility and cost).

Figure 3.4 Risk assessment in the decision‐making process.