Pragmatic vs. Explanatory - Efficacy vs. Effectiveness
| Feature | Explanatory Trial | Pragmatic Trial |
|---|---|---|
| Question | Can it work? (Efficacy) | Does it work in practice? (Effectiveness) |
| Setting | Ideal, controlled conditions | Real-world, routine care |
| Participants | Homogeneous, highly selected | Heterogeneous, diverse |
| Validity | High internal validity | High external validity (generalizability) |
⭐ Most new drug approvals are based on explanatory trials showing efficacy under ideal conditions. Post-marketing studies are often pragmatic to assess real-world effectiveness.
Trial Showdown - Ideal Lab vs. Messy Clinic
| Feature | Explanatory Trial (Efficacy) | Pragmatic Trial (Effectiveness) |
|---|---|---|
| Question | Can the intervention work in ideal conditions? | Does the intervention work in real-world practice? |
| Setting | Tightly controlled, "lab" setting | Routine clinical practice, "messy clinic" |
| Participants | Homogeneous, strict inclusion/exclusion | Heterogeneous, broad, reflects patient population |
| Intervention | Rigid protocol, focus on adherence | Flexible, reflects variations in usual care |
| Validity | ↑ Internal Validity | ↑ External Validity (Generalizability) |
| Goal | Test a scientific hypothesis | Inform clinical & policy decisions |
Choosing Your Weapon - Which Trial When?
| Feature | Explanatory (Efficacy) | Pragmatic (Effectiveness) |
|---|---|---|
| Goal | Can it work? (Ideal conditions) | Does it work? (Real-world) |
| Setting | Tightly controlled, research setting | Everyday clinical practice |
| Patients | Homogeneous, strict inclusion | Heterogeneous, broad population |
| Validity | High internal validity | High external validity |
High‑Yield Points - ⚡ Biggest Takeaways
- Explanatory trials test efficacy in ideal, controlled settings with homogenous populations, maximizing internal validity.
- Pragmatic trials test effectiveness in real-world clinical practice with heterogeneous populations, maximizing external validity (generalizability).
- The core question for explanatory trials is: "Can it work?"
- The core question for pragmatic trials is: "Does it work in the real world?"
- There is an inherent trade-off between internal and external validity.
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