skip to primary navigation skip to content

SSA Toolkit

The SSA process


The SSA process

The SSA process

The System Safety Assessment (SSA) process comprises four phases: Examine, Assess, Improve and Manage. The diagram on the right provides a framework for understanding how these fit together, which is also explored in more detail below. Each of the phases contains several activities, which are shown on an expanded version of the diagram later on this page. More detail on each of these activities can found in the separate sections on Examine, Assess, Improve and Manage.

On this page:

The SSA process consists of the Examine, Assess and Improve phases, guided and informed by Manage

The SSA process comprises Examine, Assess, Improve and Manage phases

Four key questions

The four phases of the SSA process address a set of key questions:

  1. What is going on?
    (in the system under examination)
  2. What could go wrong?
    (in this system)
  3. What can we do about it?
  4. What should we do next?
    (in the SSA)?

The diagram opposite shows how these questions are answered through cycles of Examine, Assess and Improve guided by the Manage element of the process.

In more detail:

  1. The Examine phase examines what is currently happening in the system under examination.
  2. The Assess phase identifies potential problems, i.e. the things that could go wrong in this system.
  3. The Improve phase proposes and implements ways to address these problems.
  4. The Manage element guides the process, helping to determine what activity to do next to keep the assessment on track.
Each stage in the SSA process addresses a key question. Examine addresses What is going on? Assess looks at What could go wrong? Improve looks at What can we do about it? And Manage focuses on What should we do next in the SSA?

Four key questions in an SSA

Repeated cycles of assessment

The SSA process is typically iterative, with repeated cycles of Examine, Assess and Improve leading to a greater understanding of the system and better ways of addressing the risk in it. The phases are listed in the order in which they naturally occur. However, what you learn in later phases can make you revisit earlier ones. For example, what you learn in Assess and Improve could cause you to return to Examine to broaden the scope of the assessment. Similarly, what you learn in Improve could make you return to Assess to rethink some of the risks.

The Manage element of the SSA guides this process, helping the team to identify the most appropriate steps to undertake at each point in time.

An SSA involves repeated cycles of the phases

Iteration is important for achieving a good SSA

Map of key activities

The four questions in an SSA can be expanded into a map showing the main activities that comprise the process. Each of the phases contains several activities, which are shown in the order in which they naturally occur. This order is not fixed. It may be helpful to move backwards and forwards between them, as the SSA develops.

The SSA process starts with Record background in the Examine phase, and follows round the outer circle of the diagram. The Manage activities naturally occur throughout the process. However, it is useful to explicitly set aside time to Refine goals and Plan next steps straight after Record background, since these set the agenda for subsequent activities and identify specifically what you will do during the first cycle of the SSA. Remember that, at any stage, the activities may need to be replanned, based on findings so far.

More information about each of the activities can be found in the sections about each of the phases: Examine, Assess, Improve and Manage.