5.45. When estimating risk, it is necessary to describe the approach taken to determining risk and to identify clearly whether the probabilities of occurrence of events and processes and/or scenarios were assessed, how the uncertainty associated with each scenario was dealt with, and which scenarios were included in the risk evaluations. If probabilities of occurrence of events and processes are used in risk calculations, the results can be compared to risk criteria. If the probability of occurrence of each scenario is not used - so that only doses or risks conditional on the occurrence of the scenario are calculated - it should be explained how the assessment results from various scenarios are compared to any regulatory criteria on risk.