Exploring the science of complexitySystems and complexity

Exploring the science of complexity series (part 3): Executive summary

This article is part 3 of a series of articles featuring the ODI Working Paper Exploring the science of complexity: Ideas and implications for development and humanitarian efforts.


The key concepts of complexity science provide a means of understanding dynamics and processes of change found in a range of physical and biological phenomena. Complexity science as it stands at the present day is a collection of ideas and principles, many of which have been influenced by other bodies of knowledge. Increasing attention is now being paid to how these concepts can help researchers and practitioners understand and influence social, economic and political phenomena. There is energetic debate occurring around their relevance and applicability outside their discipline of origin.

In the international development and humanitarian spheres, work in this area has grown relatively slowly. The application of complexity science to human realms has by no means been non-contentious: it has its champions, pragmatists and critics (for more on this, see the conclusions to this executive summary). This [series] … explores and explains the key concepts of complexity science, then moving on to reflect on the implications of the concepts, before arriving at some general conclusions about what complexity science means for development and humanitarian efforts. It is hoped that the conclusions may be of use for the busy policy advisors, overstretched managers and time-constrained evaluators and researchers who are interested in improving reform and change efforts, and keen to better understand how complexity science relates to such efforts and, by extension, the future of the sector.

Key concepts of complexity science

The [series] … details each of the 10 concepts of complexity science, using real world examples where possible. It then examines the implications of each concept for those working in the aid world. Here, we list the 10 concepts for reference, using the next section of this summary to suggest some overall implications of using the concepts for work in international development and humanitarian spheres.

The ten concepts are as follows:

  • Interconnected and interdependent elements and dimensions
  • Feedback processes promote and inhibit change within systems
  • System characteristics and behaviours emerge from simple rules of interaction
  • Nonlinearity
  • Sensitivity to initial conditions
  • Phase space – the ‘space of the possible’
  • Attractors, chaos and the ‘edge of chaos’
  • Adaptive agents
  • Self-organisation
  • Co-evolution.


This brief conclusion attempts to bring together the above concepts and their various implications to answer a number of key questions for international development and humanitarian efforts overall.

  1. How do the concepts of complexity science fit together? Complexity concepts are best described as a loose network of interconnected and interdependent ideas. Their relevance and applicability may be best seen through empirical studies of practical realities. A firm foundation for complexity may never be achieved; it may be that there is a need to become better accustomed to a network-oriented model of how knowledge and ideas relate to each other, instead of a classical model of knowledge which focuses on ‘foundations’ , ‘pillars’, etc.
  1. What do the complexity science concepts offer to those facing international development and humanitarian problems? The debate on this subject continues. Classical science has been described as a set of ‘useful fictions’ that enables us to cut through real world complexities. Clearly, this can oversimplify issues, and prove less than useful. Our conclusion is that complexity science offers a set of useful, challenging ‘fictions’ which enable us to better delineate and understand complexities of the real world.
  1. How does complexity science differ from existing ways of understanding and interpreting problems? Complexity steers a course between induction and deduction by aiding understanding of the mechanisms through which unpredictable, unknowable and emergent change happens. This enables a reinterpretation of existing systems and problems faced within them. Complexity generates insights that help with looking at complex problems in a more realistic and holistic way, thereby supporting more useful intuitions and actions.
  1. What kinds of phenomena can complexity science help us better understand? There are multiple ways in which the work carried out by development and humanitarian agencies can be seen as taking place within complex systems. Complexity science can prove particularly useful in allowing us to embrace what were previously seen as ‘messy realities’. This might allow comparisons between cases and systems previously not related, potentially strengthening insight and helping to highlight possible effective actions.
  1. What is the value of complexity science for those engaged in humanitarian and development work? Does it tell us anything new? The concepts of complexity theory provide a series of important stepping stones towards a more realistic understanding of the limitations of aid as well of the factors involved in ‘messy realities’. As to whether complexity science tells us anything new: 1) it allows old concepts to be understood in different ways; 2) it allows for new generalisations about certain kinds of phenomena; and 3) it has unique concepts of its own, such as sensitive dependence on initial conditions, already manifest in the idea of path dependence in neoclassical economics.
  1. What kinds of practical uses are there for complexity science in international aid? In particular, qualitative and quantitative approaches have a lot more in common when seen using the light of complexity. The concepts can be used individually or in combination, to reflect on an individual phenomenon, the overall system, or specific sub-systems. They can be used ex-ante and ex-post, to augment existing models or as a framework in their own right. In sum, they can be used in a highly flexible manner. Future collaborative work might prove especially useful in identifying the range and scope of the concepts.

At the start of this exploration, our view was that complexity would be a very interesting place to visit. At the end, we are of the opinion that many of us in the aid world live with complexity daily. There is a real need to start to recognise this explicitly. Whether solutions to longstanding problems can be arrived at using complexity thinking will become clearer when those individuals and institutions working in international aid start consciously and deliberately to use the complexity lens.

We have tried to be aware of the different attitudes towards complexity science and not overextend the concepts’ potential applications. Perhaps the greatest challenge lying in complex systems stems from the fact that they fundamentally state that the best course of action will be highly context-dependent. For this reason, we realise that many of the implications here are at a meta-level, in that they suggest new ways to think about problems and new questions that should be posed and answered, rather than concrete steps that should be taken as a result.

Given the scope for new ideas, the most serious implication of complexity science for international aid is the inability or unwillingness to engage with complexity in aid policy and practice. Meanwhile, the financial and political costs of bringing a complexity framework to bear on development and humanitarian problems are far from trivial.

Four changes seem to be particular importance: the openness to new ideas, the restraint to accept the limitations of the approach; the honesty and humbleness to accept the limitations of aid efforts and to accept mistakes, and the courage to face up to the implications of these ideas.

Next part (part 4): Introduction.

Article source: Ramalingam, B., Jones, H., Reba, T., & Young, J. (2008). Exploring the science of complexity: Ideas and implications for development and humanitarian efforts (Vol. 285). London: ODI. (https://www.odi.org/publications/583-exploring-science-complexity-ideas-and-implications-development-and-humanitarian-efforts). Republished under CC BY-NC-ND 4.0 in accordance with the Terms and conditions of the ODI website.

Header image source: qimono on Pixabay, Public Domain.

Ben Ramalingam and Harry Jones with Toussaint Reba and John Young

Authors of the Overseas Development Institute (ODI) Working Paper "Exploring the science of complexity: Ideas and implications for development and humanitarian efforts".

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