| Term | Definition |
|---|---|
| Effectiveness | Effectiveness assesses whether an intervention is beneficial when provided under usual circumstances of healthcare practice (“Does it work in practice?”)55 |
| Pragmatic RCT Used interchangeably with “effectiveness RCT” |
An RCT intended to directly inform clinical or health policy decision-making, usually investigating therapeutic effectiveness or comparative effectiveness under conditions similar to clinical practice46,82,117 |
| Real-world evidence | “Information on health care that is derived from multiple sources outside typical clinical research settings, including electronic health records […], […] billing data, […] registries, and […] through personal devices and health applications.” (p. 2293).119 Real-world data are distinct from pragmatic trial data, in that the latter are collected in a specifically designed research paradigm and real-world evidence from unmodified clinical practice. |
| Generalizability Used interchangeably with “external validity” and “applicability”109,110 |
The degree to which trial results may be considered valid in and applicable to participants, practitioners, interventions, outcome measures, and settings outside the respective trial30,109,110 |
| Internal validity | “Internal validity describes the […] accuracy of the study results by minimizing error. Thus, internal validity is the degree to which changes in the dependent variable can be attributed to the intervention and is maximized by decreasing bias using design features such as random assignment, allocation concealment, and blinding” (p. 164)140 |
| Efficacy | Efficacy is the extent to which an intervention provides benefit under ideal circumstances (“Can it work?”)55 |
| Explanatory RCT Used interchangeably with “efficacy RCT” |
An RCT that tests the benefits and/or harms of a treatment under relatively ideal conditions, aimed primarily at investigating a scientific or biological problem46,82,117 |
| Mechanistic RCT | An RCT that investigates treatment mechanisms under relatively ideal conditions (alongside benefits and harms or exclusively) |
RCT, randomized controlled trial.