Identifying essential elements of a complex intervention

This series showcases the contributions of Sax Institute researchers to papers published in peer-reviewed literature.

What was studied?

The paper looked at how to assess the fidelity of complex interventions that are informed by composite theory (e.g. different social and psychological theories), and which incorporate both standardised and flexible components. Fidelity assessment tells us how interventions are delivered.

The researchers focused on essential elements, i.e. aspects of the intervention that embody the program theory and which must be delivered if the intervention is to be successful. They asked: “How can we determine which parts of the intervention really are essential, and which can be adapted without impairing its effectiveness? And how can we do this in the context of a complex intervention trial?”

This work took place during Supporting Policy In health with Research: an Intervention Trial (SPIRIT). SPIRIT is testing the effects of a suite of strategies designed to increase the capacity of health policy agencies to use research.

What are the key findings?

The researchers  developed a process for identifying, critiquing and refining essential elements while the intervention was in progress (i.e. while also using them as fidelity indicators). They identified over 50 provisional elements of SPIRIT, refining them to a final list of 20 essential elements.

They identified six factors that challenged the validity of essential elements:

  1. Redundant – the element was not essential
  2. Poorly articulated – the element was unclear, too specific, or not specific enough
  3. Infeasible – it wasn’t possible to implement the essential element as intended
  4. Ineffective – the element didn’t effectively deliver the program theory
  5. Paradoxical – the element counteracted the program theory or the intervention goals
  6. Absent or suboptimal – additional or more effective ways of putting the theory into practice were identified

The study also identified “prohibited” elements ‒ aspects of the trial that impaired effectiveness and should be minimised or eradicated.

What was the conclusion?

Identifying an intervention’s essential elements and monitoring them as part of fidelity assessment was critical for understanding how the intervention worked or why it didn’t work, the researchers said.

They concluded that their approach could be used or adapted for other complex interventions, and might help other researchers to make theoretically and contextually sensitive decisions about what elements to focus on in fidelity assessment.

The paper

Haynes A, Brennan S, Redman S, Williamson A, Gallego G, Butow P and The CIPHER team. Figuring out fidelity: a worked example of the methods used to identify, critique and revise the essential elements of contextualised intervention in health policy agencies. Implementation Science 2016:11:23 [Internet] DOI: 10.1186/S13012-016-0378-6