12/24/2025
**Mastering Your Research: A Guide to Internal vs. External Validity**
For any MPH student, understanding the two pillars of study validity is non-negotiable. They determine the strength and significance of your research findings.
🔬 **Internal Validity: The Cause-and-Effect Question**
This is the confidence that your intervention (e.g., a health program) directly caused the observed results.
- **Key Question:** Did the treatment work?
- **Focus:** Reducing internal bias through control groups and random assignment.
- **Threats:** History, maturation, selection bias.
🌍 **External Validity: The Generalizability Question**
This is the extent to which your study's results can be applied to other populations, settings, or times.
- **Key Question:** Does this apply to real life?
- **Focus:** Broadening your study's reach.
- **Threats:** Limited settings, narrow samples.
⚖️ **The Balancing Act**
Great research isn't just about proving a point in a lab; it's about discovering truths that can be applied to improve community health. This requires a careful balance between controlling for bias (internal validity) and ensuring your findings are relevant to the wider world (external validity).
Want a quick video breakdown of this concept? Watch our YouTube Short!
https://youtube.com/shorts/fBLCFWsP5Zo?feature=share
