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Table 6 Support for proposition 2 - complex interventions evolve and change

From: Intervention description is not enough: evidence from an in-depth multiple case study on the untold role and impact of context in randomised controlled trials of seven complex interventions

Findings in support of proposition

Evidence source

 

Trial 1

Trial 2

Trial 3

Trial 4

Trial 5

Trial 6

Trial 7

1. Standardising complex interventions is challenging, because interventions may frequently be inseparable from contexts and contexts themselves are rarely static.

✓✓

✓✓

✓✓

✓✓

✓✓

 

✓✓

2. Researchers generally have a theory of how the intervention and trial should work but this is not always made explicit. Theories of how an intervention actually should or does work can also change as contextual information becomes more apparent.

✓✓

✓✓

✓

✓✓

✓✓

✓✓

✓✓

3. Relationships between people involved in complex intervention trials evolve and change thereby changing the intervention.

✓

✓

  

✓

✓

 

4. Complex intervention trials have a knock-on effect on the practice context, which may then lead to further evolution and change in the intervention.

✓✓

✓

 

✓✓

✓

 

✓✓

  1. ✓ = some evidence (one instance); ✓✓ = strong evidence (more than one instance); no check/tick = no specific evidence.