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Relative Risk
Aka: Relative Risk
- See Also
- Odds Ratio
- Weighted Mean Difference
- Definition
- Relative Risk
- Ratio of probability of an event in an exposed group to that in an unexposed group
- Evaluation
- Calculation
- Relative Risk = P(disease I exposure) / P(disease I No exposure)
- Example
- Exposure to Substance X
- Disease Y Contracted in 25
- Disease Y NOT Contracted in 75
- NO Exposure to Substance X
- Disease Y Contracted in 10
- Disease Y NOT Contracted in 190
- Probabilities
- P(disease | exposure) = 25 / (25 + 75) = 0.25
- P(disease | No exposure) = 10 / (10 + 190) = 0.05
- Conclusion
- Relative Risk = P(disease I exposure) / P(disease I No exposure) = 0.25/0.05 = 5
- Patients exposed to Substance X are 5 times more likely to develop disease Y
- Resources
- Wikipedia
- https://en.wikipedia.org/wiki/Likelihood_ratios_in_diagnostic_testing
- Smart Health Choices
- http://www.ncbi.nlm.nih.gov/books/NBK63647/
- References
- Desai (2014) Clinical Decision Making, AMIA’s CIBRC Online Course