Epi

Relative Risk

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Relative Risk

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