Composite risk index: the new Safety Performance Indicator of risk exposure

Conceptually, all safety programmes desire accurate safety risk quantification in order to provide a meaningful expression of risk. As there are typically, multiple safety risks associated with a system or event, the quantification of total safety risk is a major challenge. One possible way to define and accept the total safety risk of any system is using the concept of a composite risk estimate. This paper represents development of the new safety performance indicator and overall methodology that could be used to measure the performance of European ATM systems as a whole and its individual entities. It describes the computation of the Composite Risk Index (CRI), logic behind it, its use (on the example EUROCONTROL Member States) and limitations and areas of potential improvement. CRI represents a cumulative risk value calculated aggregating all reported, assessed and severity classified key safety-related incidents to form an index. This measure of risk exposure is based on probability and severity that considers the human perception of equivalent risk. Overall idea behind CRI is that the performance of safety system can be analysed within three important broad categories: the quality of reporting system with reporting entity, measured risks within the system, and human perception of risk.