Concepts and definitions in Systems

Concepts and definitions in Systems

It can be challenging to come to an agreement on shared definitions and concepts , especially when collaborating between different disciplines (such as engineering and social sciences), methodologies and schools of thought. 

To help us navigate this, we have brought together some key concepts and definitions. We recognise that meanings can vary depending on the context so we are aware these terms may have different interpretations in other contexts, disciplines and regions.

Basic definitions

Considerations about navigating complex systems 

A measure of a system's complexity can be defined as the difficulty to understand how a system will behave or to predict the consequences of changing it. In engineered systems, effort is focused on managing complexity to bring out the desired behaviours of the system.  For example, efforts to improve system security can reduce system safety. This can lead to challenging trade-off decisions and unintended consequences when seeking to affect system behaviours.  Examples of complex systems can be find in the real world such as infrastructures like transportation, power grids and communication systems. 

There are some considerations to keep in mind when navigating complex systems.

Complex systems do not have clear boundaries

The system boundary may vary depending on the perspective or problem being considered.  This can be demonstrated in the concept of a system of interest. This is where a system boundary is defined but for a particular context based judgement and a partial leaning towards it. Challenges arise when leaders place too many constraints on the system being considered. 

Complexity is not determined simply by the size of a system or the number of parts

Consider a system with many similar parts that are all acting in well-known and predictable ways. While this may be a large system, its overall complexity is low. It is not difficult to predict how the system will behave, even when a new stimulus or change in the environment occurs.

Complex systems are often not purposely designed as a whole; instead, they emerge and evolve

This means they may not have a single designer or architect. While some parts of the system may be engineered, other parts can appear to be simple or complicated. Connections across the complex system may not be necessarily intentional and can be challenging to recognise or understand. Even if few elements interact, the effects can be distributed across the system, often which are nonlinear.

Complexity is not binary and complex systems are often not wholly complex

Complexity can vary, making it harder to pinpoint when a system is complex or is not. There are various factors that can contribute to it's complexity; some of which can influence the success of interventions to the system. Some find it useful to use terms like subjective and objective complexity to distinguish areas that are addressable and understandable given the right expertise and approach.

How to handle complexity? 

As an attempt to deal with complex issues, different methods, frameworks and ways of understanding a complex system have surfaced. We will refer to those as systems approaches.

A systems approach is a holistic and interdisciplinary way of understanding and solving complex problems. It sees the world as a collection of interconnected and interdependent elements, people and highlights the connections and relationships between them. A true systems approach doesn't only deliver technical solutions, it ensures technology, processes, interactions and policy are appropriately aligned to deliver innovative solutions to today’s most complex and pressing challenges.

Systems approaches can be used in different ways, themes and project management. In the programme, we have started to explore decision-making processes that govern these complex systems or what we also call governance mechanisms. This is aimed at energising collective action towards a specific challenge (achieving just energy transition and fair access to all).

Explore more on how the Royal Academy of Engineering offer system's through applied systems approaches in policy, our compilation of case studies that provide insights into how the design, construction, operation, management and governance of complex systems may result in safe or unsafe outcomes.