We've noticed you're using an outdated browser. For full compatibility, please ensure you're running a modern browser such as Google Chrome, Firefox, Safari or Microsoft Edge.

Systems Thinking

Why are systems important?

The idea of a system as 'a set of parts which, when combined, have qualities that are not present in any of the parts themselves' is a very productive way of looking at the world – which turns out to be full of systems. Many engineered systems are much broader than the association with 'engineering' might imply: the 'elements' or 'parts' of a system may include, for example, people, processes, information, organisations and services, as well as software, hardware and complex products.

The qualities that 'emerge' at the level of the whole also deserve a special mention.  They arise when system elements interact with each other and their environment, and indeed only exist when the components of a system are able to interact.  Although 'emergence' brings the risk of unintended consequences, a major cause of embarrassing system and project failures, skilled systems engineers can create higher value for less cost by using emergence to deliver desired system qualities.

Systems Thinking is a way of thinking used to address complex and uncertain real world problems.  It recognises that the world is a set of highly interconnected technical and social entities which are hierarchically organised producing emergent behaviour.

Two useful definitions

"Systems Thinking enables you to grasp and manage situations of complexity and uncertainty in which there are no simple answers. It’s a way of learning your way to effective action by looking at connected wholes rather than separate parts. It is sometimes called practical holism."  [Open University definition]

"Systems thinking is a framework for seeing interrelationships rather than things, for seeing patterns rather then static snapshots. It is a set of general principles spanning fields as diverse as physical and social sciences, engineering and management."  [Peter Senge , The Fifth Discipline]

Relationship with Systems Engineering

Systems Thinking is an essential skill for Systems Engineers which is shared with many disciplines and provides a key intellectual underpinning for Systems Engineering.

Systems Thinkers recognise that -


  • through their perceptions, determine purpose, use process to deliver performance and use change in patterns to measure progress;
  • understand the need to be good team players;
  • are our customers, stakeholders, designers, developers and users;
  • have varying levels of rationality, intentionality and even perversity;
  • have belief systems, perceptions and viewpoints developed through culture, training and views of best practice within disciplines;
  • are not separate from the problem, project or programme with which they are engaged. They are an integral part of System Thinking models.

Performance measurement...

  • needs to be supported by evidence and suitably monitored to ensure that the purpose of the system is being fulfilled;
  • will need to be a combination of quantitative and qualitative measures that communicate a historical and forward view of performance;
  • is often done inappropriately because people choose to measure what is easy to measure, rather than what needs to be measured to ensure that purpose is delivered.


  • is an inevitable attribute of a complex system.
  • is managed by first recognising what we do not know and expecting unintended consequences particularly when new systems are being introduced or systems are used in a different context.
  • requires the inclusion of feedback and feed-forward learning loops in the process to minimise its impact.

Benefits of Systems Thinking

Systems thinking provides a rigorous way of integrating people, purpose, process and performance; and also:

  • relating systems to their environment;
  • understanding complex problem situations;
  • maximising the outcomes achieved;
  • avoiding or minimising the impact of unintended consequences;
  • aligning teams, disciplines, specialisms and interest groups;
  • managing uncertainty, risk and opportunity.

A Systems Thinker’s Goal is to fulfil Purpose

  • Purpose is the result, outcome or effect that is intended from the system. Purpose is the answer to the question: Why are we doing this process? It is  the driver of intended change and defines unintended consequences.
  • A requirement is an unambiguous statement of the capability that the system must deliver. A requirement is expressed in operational terms (what the system will do) rather than solutions (how the system will do it).
  • Effective requirements can only be produced once purpose is clear.