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Risk Ratio Formula:
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Risk Ratio (also known as Relative Risk) is a measure used in epidemiology to compare the risk of a health event between two groups. It represents the ratio of the probability of an event occurring in the exposed group versus the control group.
The calculator uses the Risk Ratio formula:
Where:
Explanation: The Risk Ratio quantifies how much more (or less) likely an outcome is to occur in the exposed group compared to the control group.
Details: Risk Ratio is crucial in medical research, public health studies, and clinical trials to assess the strength of association between exposure and outcome. It helps determine if an exposure increases or decreases the risk of a particular outcome.
Tips: Enter both risk values as fractions (between 0 and 1). Risk Exposed represents the risk in the group exposed to the factor, while Risk Control represents the risk in the unexposed control group.
Q1: What does a Risk Ratio of 1 mean?
A: A Risk Ratio of 1 indicates no difference in risk between the exposed and control groups. The exposure does not affect the outcome.
Q2: What does a Risk Ratio greater than 1 indicate?
A: A Risk Ratio greater than 1 suggests that the exposure increases the risk of the outcome. The higher the value, the stronger the association.
Q3: What does a Risk Ratio less than 1 indicate?
A: A Risk Ratio less than 1 suggests that the exposure decreases the risk of the outcome, potentially having a protective effect.
Q4: How is Risk Ratio different from Odds Ratio?
A: Risk Ratio uses probabilities, while Odds Ratio uses odds. Risk Ratio is more intuitive for interpreting risk differences, especially in cohort studies.
Q5: When should Risk Ratio not be used?
A: Risk Ratio may not be appropriate in case-control studies where the true risk cannot be calculated directly. Odds Ratio is preferred in such designs.