The most valuable feature of systems assessment is its ability to provide insight about what might happen in the future, under a range of different circumstances. Knowing these possible consequences enables better decisions to be taken, e.g. about how to manage a hazardous material. However, it is important to very carefully identify what scenarios are examined in an assessment. In order to get a balanced understanding of what might happen, the scenarios investigated need to be comprehensive but not implausible, and relevant to the issue being considered.

Quintessa has been at the forefront of developing and applying systematic scenario identification methods for many years. Staff played leading roles in international programmes to develop scenario approaches for nuclear waste in the 1980s and 1990s which have since been very widely used. More recently we have taken these ideas (such as the concept of Features, Events and Processes) and applied them to areas such as the safety of CO2 in Carbon Capture and Storage. We also recognise the importance of communicating and justifying scenarios (our work for national and international clients has often been scrutinised by regulators) and work to document and illustrate them in clear ways.