Epidemiology Concepts

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Questions and Answers

What is the primary purpose of the epidemiological triangle?

To identify disease causes and prevention strategies (correct)

To conduct hypothesis testing

To calculate the attack rate

To determine disease prevalence

What does the PPV measure?

The probability that individuals with a positive test result actually have the disease (correct)

The sensitivity of a diagnostic test

The specificity of a diagnostic test

The probability of a false positive test result

What is the main difference between an epidemic and a pandemic?

The type of disease involved

The duration of the outbreak

The number of cases involved

The geographical area affected (correct)

What type of study is the odds ratio typically used in?

Case-control study Signup and view all the answers

What is selection bias an example of?

Sampling bias Signup and view all the answers

What does the p-value represent?

The probability of obtaining results as extreme as those observed, assuming the null hypothesis is true Signup and view all the answers

What is a key distinction between incidence and prevalence?

The time period measured Signup and view all the answers

What is recall bias an example of?

Information bias Signup and view all the answers

What is the term for the phenomenon where studies with positive results are more likely to be published?

Publication bias Signup and view all the answers

Which type of bias occurs when participants provide inaccurate responses due to social desirability or pressure?

Response bias Signup and view all the answers

What is the term for the phenomenon where only those who survive a condition or event are included in the sample?

Survivor bias Signup and view all the answers

What is the probability that individuals with a negative test result do not have the disease?

NPV Signup and view all the answers

What is the term for making inferences about individuals based on group data?

Ecological fallacy Signup and view all the answers

What is the purpose of blinding participants and researchers to group assignments?

To reduce observer and performance biases Signup and view all the answers

What is the term for the bias that occurs when there is selective revealing or suppression of information?

Reporting bias Signup and view all the answers

What is the term for a test's ability to correctly identify those with the disease?

Sensitivity Signup and view all the answers

Study Notes

Epidemiological Triangle

The epidemiological triangle consists of three components: agent, host, and environment, which helps in identifying disease causes and prevention strategies.

Disease Measurement and Analysis

Positive Predictive Value (PPV) is the probability that individuals with a positive test result actually have the disease, dependent on test sensitivity, specificity, and disease prevalence.
Odds ratio compares the odds of an event occurring in an exposed group to a non-exposed group, useful in case-control studies.
Inferential statistics allow conclusions about a population based on sample data, using hypothesis testing, confidence intervals, and regression analysis.
A p-value indicates the probability of obtaining results as extreme as those observed, assuming the null hypothesis is true; a value less than 0.05 suggests significance.

Disease Occurrence

Attack rate is the proportion of exposed individuals who develop the disease, used during outbreaks to determine risk.
Endemic disease is consistently present in a specific area or population, representing a stable disease state.
Epidemic is a sudden increase in cases above normal expectations in a specific area.
Pandemic is an epidemic that has spread across countries or continents, affecting a large number of people.
Prevalence measures the proportion of individuals with a specific disease at a given time or over a specific period.
Incidence refers to the number of new cases of a disease in a population during a specific period, indicating risk.

Biases in Research

Selection bias occurs when study participants are not representative of the target population.
Information bias arises from systematic errors in measurement or classification of variables.
Confounding bias occurs when the effect of the primary exposure on an outcome is mixed with an extraneous factor.
Recall bias happens when participants inaccurately remember past events or exposures, common in retrospective studies.
Observer bias occurs when researcher expectations influence outcome assessment; blinding observers can reduce this.
Publication bias occurs when studies with positive results are more likely to be published, skewing the literature.
Response bias occurs when participants provide inaccurate responses due to social desirability or pressure.
Survivor bias happens when only those who survive a condition or event are included in the sample.
Healthy worker effect occurs when workers exhibit lower morbidity and mortality rates than the general population.
Attrition bias arises when participants drop out, and the remaining differ significantly from those who left.
Detection bias occurs when outcome determination differs across study groups; consistent assessment methods can help.
Misclassification bias happens when participants are incorrectly categorized regarding exposure or outcome status.
Ecological fallacy refers to making inferences about individuals based on group data.

Minimizing Biases

Recall bias can be minimized using standardized questionnaires and validating reported information.
Blinding participants and researchers to group assignments reduces observer and performance biases.
Randomization helps distribute confounders evenly between groups, reducing selection bias.
Matching pairs cases and controls with similar characteristics to control for confounding variables.
Adjusting for confounders with statistical methods ensures the observed association is unbiased.
Reporting bias can be mitigated by encouraging full and honest reporting.

Diagnostic Testing

NPV is the probability that individuals with a negative test result do not have the disease, crucial for ruling out disease.
Sensitivity measures a test's ability to correctly identify those with the disease, important for screening programs.
Specificity measures a test's ability to correctly identify those without the disease, reducing false positives.
Validity refers to how well a test measures what it's supposed to measure, indicating accuracy.

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Description

Learn about the epidemiological triangle, PPV, odds ratio, and inferential statistics in epidemiology and disease prevention.