Key Concepts in Screening Statistics
Mar 21, 2025
1. Sensitivity:
- Definition: Sensitivity is the ability of a test to correctly identify those who have the disease (true positive rate).
- Calculation: Sensitivity = (True Positives) / (True Positives + False Negatives)
- Interpretation: A test with high sensitivity will have few false negatives, meaning it is good at identifying the disease in those who have it.
Example: If a test correctly identifies 90 out of 100 people with the disease, the sensitivity is 90%.
2. Specificity:
- Definition: Specificity is the ability of a test to correctly identify those who do not have the disease (true negative rate).
- Calculation: Specificity = (True Negatives) / (True Negatives + False Positives)
- Interpretation: A test with high specificity will have few false positives, meaning it is good at identifying those who do not have the disease.
Example: If a test correctly identifies 95 out of 100 people without the disease, the specificity is 95%.
