1. What is Relative Risk?

Relative Risk (RR) is a measure of the strength of association between an exposure and an outcome. It compares the probability of an event occurring in the exposed group versus the control group.

2. How Does the Calculator Work?

The calculator uses the Relative Risk formula:

Where:

• \( incidence\_exposed \) — Incidence rate in exposed group (unitless)
• \( incidence\_control \) — Incidence rate in control group (unitless)

Interpretation:

• RR = 1: No difference in risk between groups
• RR > 1: Increased risk in exposed group
• RR < 1: Decreased risk in exposed group

3. Importance of Relative Risk Calculation

Details: Relative Risk is widely used in epidemiology to assess the risk of developing a disease in exposed individuals compared to unexposed individuals. It helps in understanding the magnitude of association between risk factors and outcomes.

4. Using the Calculator

Tips: Enter the incidence rates for both exposed and control groups. Both values must be greater than 0. The result is unitless and represents the ratio of risks.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between RR and odds ratio?
A: RR compares probabilities directly, while odds ratio compares odds. RR is more intuitive but can't be used in case-control studies.

Q2: When is Relative Risk most appropriate?
A: RR is ideal for cohort studies and randomized controlled trials where true incidence rates can be calculated.

Q3: How should I interpret an RR of 2.5?
A: An RR of 2.5 means the exposed group has 2.5 times the risk of the outcome compared to the control group.

Q4: What are the limitations of Relative Risk?
A: RR doesn't provide information about absolute risk and can be misleading when baseline risks are very small.

Q5: Should I always aim for statistical significance with RR?
A: While statistical significance is important, also consider the clinical significance and confidence intervals when interpreting RR.