1. What is Relative Risk Reduction?

Relative Risk Reduction (RRR) is a measure of the proportional reduction in risk between the control group and the experimental group in clinical trials. It expresses how much the risk is reduced in the treatment group compared to the control group.

2. How Does the Calculator Work?

The calculator uses the RRR formula:

Where:

• \( RRR \) — Relative Risk Reduction (decimal)
• \( CER \) — Control Event Rate (decimal)
• \( EER \) — Experimental Event Rate (decimal)

Explanation: RRR represents the proportion of risk reduction in the experimental group relative to the control group risk.

3. Importance of RRR Calculation

Details: RRR is crucial in evidence-based medicine for understanding treatment effectiveness, calculating number needed to treat (NNT), and making informed clinical decisions about interventions.

4. Using the Calculator

Tips: Enter CER and EER as decimal values between 0 and 1. CER must be greater than EER for a valid RRR calculation. Values represent event rates (e.g., 0.15 for 15% event rate).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between RRR and ARR?
A: RRR shows proportional risk reduction, while ARR (Absolute Risk Reduction) shows the actual difference in risk between groups.

Q2: How do I interpret RRR values?
A: RRR of 0.5 means 50% risk reduction, 0.25 means 25% reduction. Higher RRR indicates greater treatment effectiveness.

Q3: When is RRR most useful?
A: RRR is particularly useful when baseline risks are high and you want to understand the proportional benefit of treatment.

Q4: What are the limitations of RRR?
A: RRR can be misleading when baseline risks are low, as it may overestimate clinical importance. Always consider ARR and NNT alongside RRR.

Q5: How is RRR related to NNT?
A: Number Needed to Treat (NNT) = 1/ARR. RRR helps contextualize the relative benefit that leads to the NNT calculation.