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Table 1 Assumptions made in conducting randomized controlled trials

From: Circular instead of hierarchical: methodological principles for the evaluation of complex interventions

Equipoise Patient and provider do not have a preference for a treatment
Lack of knowledge It is truly unknown which of two alternatives is "better" and there is insufficient evidence about treatment effects from other sources
Preference for specificity Only specific effects attributable to the intervention are therapeutically valid
Context independence There is a "true" magnitude of efficacy, or a stable effect size independent of context
Ecological and external validity knowable The knowledge about a therapeutic effect extracted from an RCT is readily transferable into clinical practice, if exclusion and inclusion criteria of the trial match the characteristics of a given patient