complex adaptive systems

This is a blog which is part of a series of blogs linked to my second book which can be found here:

Complexity science has evolved in part from systems theory and aims to help us understand what constitutes the complex system (and complex adaptive system) and to identify the common characteristics.  Complexity science can be used to understand the dynamic nature of the healthcare system, the relationships, the way that care is delivered and its inter-related characteristics.  To date conceptualisations of safety systems has been too superficial.  

Complexity means that a system has many variables which are continuously changing and ‘dynamic complexity’ refers to situations where cause and effect are subtle and where the effects over time of interventions are not obvious.  Complexity scientists aim to study the properties and characteristics of the entire system; the dynamics, the independent and interdependent relationships that make up the system, and the emergent behaviours of the system.  Therefore complexity science is considered an increasingly useful conceptual framework for understanding how healthcare is delivered, how people within it can be supported and how it can be optimised.

Sholom Glouberman and Brenda Zimmerman (2002) neatly describe the difference between simple, complicated and complex.

Following a cake recipe is simple.  There are clear instructions on what you need in order to make the cake down to the tiniest measurements and this is backed up with a detailed step by step guidance for using the ingredients.  The process for making the cake is usually standardised and has been tried and tested many times so that the best way to make the particular cake is there for all to use.  Success comes from following the recipe.  There are some variables; skill, scales, equipment such as ovens, the size and shape of the baking tins and so on but in the main if you follow the recipe you should get a cake at the end of it.

Sending a rocket to the moon is complicated.  It ‘sounds’ complex, but complexity scientists consider it to be complicated because it can be broken down into a series of ‘simple’ problems and tasks.  There are clearly factors that can lead to success or failure, it takes lots of different people, teams and a high level of expertise, plus lots of rules and regulations.  But similar to our cake recipe there is a likelihood that the rocket is similar to ones before it and there is so much studied and tested about the rocket that every attempt to rule out uncertainty is done.  Similar again to the cake making, the task also gets more certain over time – the more rockets sent to the moon the more assurance there is that the next one will be ok.  Once you learn how to send a rocket to the moon you can repeat the process and perfect it.  There is a degree of certainty about both what you are doing and of the outcome.  

Raising a child is complex.  Each child is unique and so raising one child will give you some experience but no assurance of success with the next one.  Expertise can help but there is no certainty of success or failure.  Each child may require an entirely different approach from the previous one.  There is huge uncertainty about the outcome and it is dependent on a massive amount of variables.  However we do know it is possible to raise a child even if it is considered complex.

Knowing the difference between the three is important because they all require different skills, different resources and responses.  Too often we try to simplify a complex problem and seek the simple solution.  We try to implement solutions that are inappropriate for the degree of complexity. t is clear that healthcare is a complex adaptive system but within it there are some processes that are complicated and in some instances just simple. 

The study of healthcare as a complex adaptive system has been considered for at least two decades (Plsek and Greenhalgh 2001, Glouberman and Zimmerman 2002).  Plsek and Greenhalgh wrote in 2001:

  • The science of complex adaptive systems provides important concepts and tools for responding to the challenges of health care in the 21st century
  • Clinical practice, organisation, information management, research, education, and professional development are interdependent and built around multiple self-adjusting and interacting systems
  • In complex systems, unpredictability and paradox are ever present, and some things will remain unknowable
  • New conceptual frameworks that incorporate a dynamic, emergent, creative, and intuitive view of the world must replace traditional “reduce and resolve” approaches to clinical care and service organisation

Common characteristics of complex adaptive systems are that of emergence and non-linear dynamics; the systems can move from, or include different areas of stability to very unstable behaviour.  This is crucial to understand as it means that techniques such as retrospective root cause analysis are difficult if not impossible in complex adaptive systems.  Characteristics of complex adaptive systems include:

  • Multiple relationships
  • Multiple components and interactions between people which are dynamic and frequently unpredictable
  • Flexible systems which do not lend themselves to standardisation
  • Interactions which are non-linear and new patterns emerge and evolve all of the time
  • Constantly adaptive people

If we want to change or improve or strengthen a complex system like healthcare we need to look for patterns in the behaviour of the system.  We need to look for interconnections within the system rather than isolated problems.  In safety this means looking at the things that occur in relation to lots of incidents and not simply the incidents in isolation.  Importantly we need to be careful when attributing cause and effect in a complex adaptive system, as we have seen it is very rarely that simple.  Equally we should be careful about prediction.  Prediction can never be certain – things happen when you least expect them to in healthcare.  Therefore keep in mind the system is dynamic, and it doesn’t necessarily respond to intended change as predicted.  

Healthcare is changing all of the time and cannot be pulled apart in the same way.  Its behaviour is also momentary so even if there is an attempt to understand it at one time or one point it will have changed before that understanding has been explained.  We owe it to people who work in the frontline of healthcare to better understand how to work in a complex adaptive system.  


Plsek P and Greenhalgh T (2001) The challenge of complexity in healthcare.  British Medical Journal

Glouberman S, Zimmerman B (2002) Complicated and Complex Systems: What would successful reform of Medicare look like? Discussion paper no 8 Commission on the Future of Health Care in Canada via