Table 3 Comparison of some key characteristics of implementation science and complexity science and their integration

Task

The task is specific: getting evidence into clinical practice in an understandable way

The task is context dependent; properties of complexity apply to biology, ecology, physics, computer science, human social systems

Tailored solutions and iterative processes

Theoretical assumptions

Heterogeneous and diverse – numerous theories, frameworks, and models

Homogenous – core assumptions of complexity science are characterized by ‘universality’ (i.e., they apply across all complex systems)

Different theories, frameworks, and models require an understanding of complexity features such as unpredictability, uncertainty, emergence, interconnection

The intervention

To be standardized to permit generalizability

To be adapted to meet needs

Factoring in complex interventions and complex settings

The context

Full of confounders, a ‘problem’ to be solved for successful implementation

An intrinsic part of a complex system; a dynamic environment that must be factored in for any intervention to be successfully taken up

For improvement to be realized, the context must be re-etched or re-inscribed such that its culture, politics, and characteristics are altered

Historical underpinnings

Evidence-based practice movement, statistics, and the scientific method

Systems theory, chaos theory; emanating from diverse scientific disciplines

More sophisticated change models can be encouraged to arise over time

Aims within health services research

- Describing or guiding the process of translating research into practice (process models)

- Understanding or explaining what influences implementation outcomes (determinant frameworks, classic theories, implementation theories)

- Evaluating implementation (evaluation frameworks)

- Description of complex system

• Understanding context

• Relationships among agents

• Dynamics

• How rules and governance structures emerge, i.e., self-organization

- For prediction rather than implementation

- Ensure that turning evidence into practice is accomplished without too many unintended negative consequences; improvement might be sustained, potentially through the adaptation of the intervention to different settings

- Implementation is not merely based on effective planning but anticipation of a range of possible outcomes

Tools and methods

Randomized controlled trials, behavior change interventions, step-wedge designs

Causal loop diagrams, system dynamics modelling, network articulations

Realist evaluation, long-term case study, participatory research, stakeholder analysis, systems mapping, social network analysis