Table 1.

Overview of the ICA approach

Aims to answer…	○ How do interventions differ from one another?
	○ Which of these differences in characteristics appears to be important?
	○ What would an ideal version of the intervention ‘look like’?
Assumes that…	○ Characteristics that are present in all/many effective interventions are worthy of attention
	○ Characteristics that may be present in one/small numbers of intervention(s) may be less important
Addresses the challenge of poor quality intervention descriptions by…	○ Using an inductive approach to explore the nature of intervention features
	○ Making use of trialists’ informally reported experience-based evidence