Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Predicting Reaction Outcomes02:24

Predicting Reaction Outcomes

11.0K
Kinetics describes the rate and path by which a reaction occurs. In contrast, thermodynamics deals with state functions and describes the properties, behavior, and components of a system. It is not concerned with the path taken by the process and cannot address the rate at which a reaction occurs. Although it does provide information about what can happen during a reaction process, it does not describe the detailed steps of what appears on an atomic or a molecular level. On the other hand,...
11.0K
Relative Risk01:12

Relative Risk

2.2K
Relative risk (RR) is a statistical measure commonly used in epidemiology to compare the likelihood of a particular event occurring between two groups. This metric is important for evaluating the relationship between exposure to a specific risk factor and the probability of a particular outcome. It plays a crucial role in medical research, public health studies, and risk assessment. Relative risk quantifies how much more (or less) likely an event is to occur in an exposed group compared to an...
2.2K
Outcomes of Glycolysis01:13

Outcomes of Glycolysis

107.8K
Nearly all the energy used by cells comes from the bonds that make up complex organic compounds. These organic compounds are broken down into simpler molecules, such as glucose. As a result, cells extract energy from glucose over many chemical reactions—a process called cellular respiration.
Cellular respiration can occur aerobically (with oxygen) or anaerobically (without oxygen). In the presence of oxygen, cellular respiration starts with glycolysis and continues with pyruvate...
107.8K
Poisson's Ratio01:23

Poisson's Ratio

1.4K
Poisson's ratio is a material property that indicates their stress response. It explains the connection between the elongation or compression a material undergoes in the direction of an applied force and the contraction or expansion it experiences perpendicular to that force. When a slender bar is loaded axially, it stretches in the direction of the force and contracts laterally. Poisson's ratio is the negative ratio of this lateral contraction to the axial elongation. The negative sign...
1.4K
Odds Ratio01:09

Odds Ratio

1.9K
The odds ratio (OR) is a statistical measure used extensively in epidemiology and research to quantify the strength of association between exposure and outcome across different groups. Unlike relative risk, which compares the probabilities of an event occurring, the odds ratio compares the odds of an event occurring in the exposed group to the odds of it occurring in the unexposed group. The odds, in this context, are calculated as the probability of the event happening divided by the...
1.9K
Hazard Ratio01:12

Hazard Ratio

632
The hazard ratio (HR) is a widely used measure in clinical trials to compare the risk of events, such as death or disease recurrence, between two groups over time. It reflects the ratio of hazard rates—the instantaneous risk of the event occurring—between a treatment group and a control group. This measure provides valuable insights into the relative effectiveness of a treatment by assessing how the risk of an event differs between the two groups.
For example, in a clinical trial...
632

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Acceptability of Nonpharmaceutical Interventions to Prevent the Risk of COVID-19 Infection in the United States.

MDM policy & practice·2026
Same author

Comparative impacts and cost-effectiveness of tuberculosis systematic screening strategies in prisons in Brazil, Colombia, and Peru: A mathematical modeling study.

PLoS medicine·2026
Same author

Migration-linked TB epidemics: How TB elimination in high-income countries depends on the success of TB control in high-burden settings.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

The global phylogeography of rapidly expanding multidrug resistant Ural lineage 4.2 Mycobacterium tuberculosis.

Nature communications·2026
Same author

Immune Priming and the Risk of COVID-19, Influenza, and Other Acute Respiratory Infections: Insights From an N3C Cohort.

Influenza and other respiratory viruses·2026
Same author

Estimating the number of incorrect tuberculosis diagnoses in low- and middle-income countries.

Nature medicine·2026

Related Experiment Video

Updated: Feb 15, 2026

A Laboratory Method to Measure Contagious Yawning in Rats
06:49

A Laboratory Method to Measure Contagious Yawning in Rats

Published on: June 14, 2019

7.5K

Risk ratios for contagious outcomes.

Olga Morozova1, Ted Cohen1, Forrest W Crawford2,3,4

  • 1Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06510, USA.

Journal of the Royal Society, Interface
|January 19, 2018
PubMed
Summary
This summary is machine-generated.

The risk ratio can be misleading for contagious diseases. This study shows how it can incorrectly suggest a risk increase when a covariate actually decreases infection risk and transmission.

Keywords:
Simpson's paradoxconfoundinginfectious diseaserisk ratiotransmission

More Related Videos

Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
19:15

Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale

Published on: August 25, 2014

88.1K
Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction
14:19

Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction

Published on: October 14, 2016

12.1K

Related Experiment Videos

Last Updated: Feb 15, 2026

A Laboratory Method to Measure Contagious Yawning in Rats
06:49

A Laboratory Method to Measure Contagious Yawning in Rats

Published on: June 14, 2019

7.5K
Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
19:15

Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale

Published on: August 25, 2014

88.1K
Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction
14:19

Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction

Published on: October 14, 2016

12.1K

Area of Science:

  • Epidemiology
  • Mathematical Biology
  • Biostatistics

Background:

  • Risk ratios are frequently used to analyze binary covariate-outcome relationships, even in scenarios with dependent outcomes like transmissible diseases in clusters.
  • Previous warnings about the misleading nature of risk ratios with contagious outcomes lack a clear understanding of the underlying error mechanisms.

Purpose of the Study:

  • To mathematically define infectious disease transmission within clusters using a stochastic susceptible-infective model.
  • To define the individual-level ratio of instantaneous infection risks as the true inferential target.
  • To evaluate the risk ratio's properties as an approximation of this target in contagious disease contexts.

Main Methods:

  • Developed a mathematical framework for infectious disease transmission dynamics in clusters.
  • Defined the individual-level ratio of instantaneous infection risks.
  • Analyzed the risk ratio's performance as an approximation using analytical methods and simulations.

Main Results:

  • Demonstrated analytically and via simulation that the risk ratio can indicate an effect opposite to the true covariate effect in contagious settings.
  • Showed that the risk ratio can exceed one even when a covariate reduces both susceptibility and transmissibility.
  • Identified confounding and Simpson's paradox as key explanations for these paradoxical findings.

Conclusions:

  • Failing to account for disease transmission in cluster studies can lead to severely misleading risk ratio estimates.
  • The risk ratio may not accurately reflect the true impact of covariates on infection risk and transmission when outcomes are contagious.
  • Careful consideration of transmission dynamics is crucial for accurate epidemiologic inference in infectious disease research.