Four Types of Human Complexity

French and colleagues articulate four dimensions of complexity which contribute to the emergence of health and social outcomes. 

Compositional complexity is underpinned by the key features of multiplicity and diversity of component parts, and by interdependency, frequency of interaction, and feedback loops defining how factors interrelate to produce emergent outcomes. Compositional complexity helps shift from thinking principally in terms of the effectiveness of individual organisations or interventions, to thinking more about how to meaningfully engage with the systems they are embedded within.  Systems science tools like causal loop diagrams help to draw attention and build a deeper understanding of composition complexity.

Experiential complexity acknowledges the diverse experiences and perspectives of individuals in determining outcomes like obesity, homelessness, or poverty. While public health approaches often consider the issues broadly, they can oversimplify the unique circumstances of different people. This can lead to standardized solutions that don't fully address individual needs and beliefs. Addressing experiential complexity requires recognizing and respecting the diversity of experiences and building a less transactional and more relational approach a to building solutions.

Dynamic complexity describes how factors within a system constantly change and interact in unpredictable ways, significantly affecting outcomes. This constant state of flux challenges the effectiveness of policies, services, and interventions, as changes in economic conditions, technology, environment, and social attitudes can quickly make current approaches obsolete. Large-scale events, like the COVID-19 pandemic or personal crises such as job loss or trauma, can suddenly shift the dynamics within a system. Dynamic complexity underscores the importance of shifting from a paradigm of accountability to one of learning.

Governance complexity refers to the task of mobilising and coordinating diverse types of knowledge, relationships and resources over time periods necessary to impact on outcomes. Outcomes ordinarily transcend organisational boundaries, fall between ring-fenced budgets, and operate across cultural divisions amongst different organisations and service sectors. Governance complexity necessitates an approach which includes stewardship, coordination and adaptation in a learning partnership.