1. What is Number Needed to Treat (NNT)?

Definition: NNT is the number of patients who need to be treated to prevent one additional bad outcome.

Purpose: It helps pediatric healthcare providers understand the effectiveness of treatments for children.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( NNT \) — Number needed to treat (dimensionless)
• \( ARR \) — Absolute risk reduction (dimensionless, between 0 and 1)

Explanation: The lower the NNT, the more effective the treatment. An NNT of 1 means every patient treated benefits.

3. Importance in Pediatric Care

Details: NNT helps evaluate treatments for children where risks and benefits must be carefully balanced.

4. Using the Calculator

Tips: Enter the absolute risk reduction (ARR) as a decimal between 0 and 1 (e.g., 0.15 for 15%).

5. Frequently Asked Questions (FAQ)

Q1: What's a good NNT value?
A: Generally, lower is better. NNT ≤ 5 is excellent, ≤ 10 is good, while ≥ 25 may be less clinically useful.

Q2: How is ARR calculated?
A: ARR = Control event rate - Experimental event rate (both as decimals).

Q3: Why is NNT important for children?
A: Children may respond differently to treatments, and NNT helps assess pediatric-specific effectiveness.

Q4: Can NNT be less than 1?
A: No, since ARR cannot exceed 1, NNT cannot be less than 1.

Q5: How should I interpret NNT for vaccines?
A: For vaccines, NNT represents the number needed to vaccinate to prevent one case of disease.