1. What is Sensitivity?

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

2. How Does the Calculator Work?

The calculator uses the sensitivity equation:

Where:

• \( TP \) — True positives (correctly identified positive cases)
• \( P \) — All actual positive cases (TP + FN)

Explanation: Sensitivity ranges from 0 to 1 (or 0% to 100%), with higher values indicating better test performance at detecting true cases.

3. Importance of Sensitivity

Details: High sensitivity tests are critical when missing a positive case could be dangerous (e.g., infectious disease screening). They minimize false negatives.

4. Using the Calculator

Tips: Enter the number of true positives and total positives. Both values must be non-negative, and P must be greater than 0. TP cannot exceed P.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between sensitivity and specificity?
A: Sensitivity measures true positive rate, while specificity measures true negative rate. They assess different aspects of test performance.

Q2: What's a good sensitivity value?
A: Generally >0.9 is excellent, 0.8-0.9 is good, but the ideal value depends on context. For life-threatening conditions, very high sensitivity is crucial.

Q3: How does sensitivity relate to recall?
A: Sensitivity and recall are identical concepts - both measure TP/(TP+FN). The terms are used in different fields (medicine vs. information retrieval).

Q4: Can sensitivity be 100%?
A: Yes, but typically at the cost of specificity. A test that always returns positive would have 100% sensitivity but 0% specificity.

Q5: When is high sensitivity most important?
A: For screening tests where missing a case is dangerous (e.g., HIV screening) or when the disease is serious and treatable.