DataTerminology.comNEW
Also known as: OR
A measure of association comparing the odds of an event in one group to the odds in another group.
DESCRIPTION
The odds ratio quantifies association strength in binary outcomes, widely used in case-control studies and logistic regression. OR > 1 indicates higher odds in the exposed group; OR < 1 indicates lower odds. Log-OR supports additive modeling and inference with confidence intervals. Interpretation requires caution versus risk ratios, especially for common outcomes. Confounding and sampling design affect estimates and generalizability.
ALTERNATIVE DEFINITIONS
Wikipedia
In statistics, the odds ratio is a measure of association between an exposure and an outcome.
Frames OR as a general association metric.
Centers for Disease Control and Prevention
The odds ratio is the ratio of the odds of an event occurring in the exposed group to the odds of it occurring in the non-exposed group.
Defines OR explicitly using exposed vs non-exposed.
BMJ
The odds ratio compares the odds of an outcome between two groups and is commonly used in case-control studies.
Links OR to case-control designs and practical use.
RELATED TERMS
Log-Odds Logistic Regression Confounding Case-Control Study Hazard Ratio Contingency Table Fisher’s Exact Test Confidence Interval
COMPETING TERMS
Relative Risk Risk Ratio
KNOWLEDGE AREAS
Mathematics Data Science Testing & Validation
TARGET AUDIENCE
Data Scientist Data Analyst BI Specialist Information Analyst Data Steward
EXTERNAL SOURCES
- Wikipedia - Odds ratio
- Cochrane Handbook - Systematic review guidance on OR
- UCLA OARC - FAQ and interpretation of OR
- Penn State Online - Logistic regression odds ratios
TOP QUESTIONS
When should the Odds Ratio be used?
OR is standard in case-control studies and logistic regression. Use RR in cohort studies when risks are estimable.
Category: Requirements
What is a common misunderstanding about Odds Ratio?
Assuming OR equals risk ratio for common outcomes; they diverge when event probabilities are not small.
Category: Misunderstanding
How is Odds Ratio interpreted?
OR = 2 means the odds of the event are twice as high in the exposed group compared to the unexposed group.
Category: Example
What are risks in using Odds Ratio?
Misinterpretation as risk can exaggerate effects; confounding and selection bias distort OR estimates.
Category: Risks
How do you compute Odds Ratio from a 2×2 table?
OR = (a/c)/(b/d) = ad/bc, where cells represent event/non-event across two groups.
Category: Requirements
How to report uncertainty around Odds Ratio?
Provide confidence intervals and p-values, often on the log scale for symmetry.
Category: Management
What alternatives compete with Odds Ratio?
Relative risk (risk ratio) and hazard ratio are used depending on design and time-to-event data.
Category: Alternatives
How does logistic regression relate to Odds Ratio?
Coefficients exponentiated yield ORs for unit changes in predictors.
Category: Example
What is a hot topic around Odds Ratio?
Communicating OR to lay audiences using probabilities or marginal effects improves clarity.
Category: Topic