Table 1.

Comparison of randomized controlled trials and real-world studies

	Randomized controlled trials	Real-world studies
Type of study	Experimental/interventional	Observational/non-interventional	Interventional/pragmatic
Design	Prospective	Retrospective/prospective	Prospective
Primary focus	Efficacy, safety, quality, cost-effectiveness	Efficacy, safety, quality, cost-effectiveness, natural history, compliance and adherence, service models, patient preferences, comparative
Patient population	Narrow, restricted, motivated	Diverse, large, and unrestricted
Monitoring	Intense (ICH-GCP compliant)	Not required (?)	Reflects usual care
Comparators	Gold standard/placebo	None/standard clinical practice/multiple iterations	Standard practice/placebo/multiple iterations
Outcomes	Clear sequence	Wide range
Data collection confounders	Standardized, controlled	Routine, recruitment bias (?), recall/interviewer bias
Randomization	Yes	No	Yes
Blinding	Yes	No	Sometimes (participants or outcome assessment)
Follow-up	Generally short	Reflects usual care	Long

ICH-GCP International Conference on Harmonisation of Good Clinical Practice