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Relative Risk Formula:
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Relative Risk (RR) is a measure of the strength of association between an exposure and an outcome. It represents the ratio of the probability of an event occurring in the exposed group versus the non-exposed group.
The calculator uses the Relative Risk formula:
Where:
Explanation: A RR of 1 indicates no difference in risk between groups. RR > 1 suggests increased risk in exposed group, while RR < 1 suggests decreased risk.
Details: Relative Risk is crucial in epidemiology and clinical research for quantifying the effect of exposures, treatments, or risk factors on health outcomes. It helps in making informed decisions about public health interventions and clinical practices.
Tips: Enter incidence rates as percentages for both exposed and unexposed groups. Incidence Unexposed must be greater than zero. The result is a dimensionless ratio.
Q1: What does a Relative Risk of 2.0 mean?
A: A RR of 2.0 means the exposed group has twice the risk of the outcome compared to the unexposed group.
Q2: How is Relative Risk different from Odds Ratio?
A: RR uses probabilities while OR uses odds. RR is more intuitive but requires cohort studies, while OR can be used in case-control studies.
Q3: When is Relative Risk most appropriate?
A: RR is most appropriate in cohort studies and randomized controlled trials where true incidence rates can be calculated.
Q4: What are the limitations of Relative Risk?
A: RR can be misleading when baseline risks are very low or very high, and it doesn't account for absolute risk differences.
Q5: How should I interpret a RR less than 1?
A: A RR < 1 indicates a protective effect - the exposed group has lower risk than the unexposed group.