1. What is Sensitivity?

Sensitivity (also called the true positive rate) measures the proportion of actual positives that are correctly identified by a test. It's a crucial metric in evaluating diagnostic tests.

2. How Does the Calculator Work?

The calculator uses the sensitivity formula:

Where:

• \( TP \) — True positives (correctly identified cases)
• \( FN \) — False negatives (missed cases)

Explanation: The formula calculates the ratio of correctly identified positive cases to all actual positive cases.

3. Importance of Sensitivity Calculation

Details: High sensitivity is critical when the cost of missing a case is high (e.g., infectious diseases). A test with 100% sensitivity means all diseased individuals are correctly identified.

4. Using the Calculator

Tips: Enter the number of true positives and false negatives from your test results. Both values must be non-negative and their sum must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What's a good sensitivity value?
A: Generally >90% is good, but depends on context. For life-threatening conditions, >99% may be needed.

Q2: How does sensitivity relate to specificity?
A: Sensitivity measures true positive rate, while specificity measures true negative rate. There's often a trade-off between them.

Q3: When is high sensitivity most important?
A: When missing a case has severe consequences (e.g., HIV screening, cancer detection).

Q4: Can sensitivity be 100%?
A: In theory yes, but in practice this usually requires compromising specificity (more false positives).

Q5: What affects sensitivity?
A: Test quality, disease stage, cutoff values, and population characteristics all influence sensitivity.