ABSTRACT Adopted for use in Shell Expro in 1989, the Incident Potential Matrix is a tool used to assess an incident in terms of ‘what might have happened’, the initial assessment being made by the immediate line supervisor and the appropriate category of ‘potential’ entered on the Incident Report Form. This may be reviewed and confirmed, eg by the incident investigation team and/or line management. The category of ‘potential’, known as the Potential Matrix Factor, can be used to assist management to determine the appropriate level of incident investigation and to target efforts to prevent a recurrence. All incidents reported within Shell Expro are assessed in this way, and the results collated for statistical purposes and to enable management to form a judgement as to the significance of the types and nature of incidents occurring. Evidence showed that the Lost Time Injury Frequency Rate, whilst considered to be a key indicator of safety performance, represented only a small minority, circa 10%, of total injury and damage incidents reported in Shell Expro. Furthermore the significance of the Lost Time Injury in terms of its potential for escalation was neither identified or recorded. In 1988 the idea of constructing a device to provide a broader, more meaningful indicator of safety performance, which would assist management to focus on the more significant incidents, was developed, and introduced the following year. The paper will explain the use of the Matrix with worked examples and elaborate on how the results are analysed. The benefits of this approach will be balanced against some of the problems experienced to date in its use.