Module 1 (History & Basics)
Which historical figure pioneered the calculation of Standardized Mortality Rates?
William Farr
How is a "Fixed Population" defined in epidemiology?
A population whose membership is permanent and defined by a life event
Which measure of association gives information about the strength of the relationship between exposure and disease and is most useful for etiologic research?
Relative Risk (RR)
What is a primary data source compared to a secondary data source?
Primary data is collected firsthand for a specific research aim, whereas secondary data utilizes pre-existing datasets collected for another purpose
Screening, which is applied to an ___ population, usually falls under the ___ level of prevention.
Asymptomatic; secondary
Sir Austin Bradford Hill's Streptomycin in Tuberculosis Trial famously featured which methodological approach?
Randomization when assigning patients to the streptomycin and control groups
When a population is in steady state, what is the exact mathematical relationship between Prevalence (P), Incidence Rate (IR), and Duration (D)?
P = IR x D
Given no association between exposure and disease, what is the value of the Risk Difference?
Risk difference = 0
What is the primary difference between active surveillance and passive surveillance?
Active surveillance involves public health staff proactively reaching out to collect data, whereas passive surveillance relies on healthcare providers voluntarily submitting reports.
Which bias occurs when a screening program appears to increase the 5-year survival rate because it selects for those who have longer preclinical stages?
Length Bias
Why is it sometimes difficult to transfer information garnered by controlled experiments of basic scientists to real-life public health initiatives?
Controlled experiments eliminate many real-world aspects to regulate the environment, making the results too artificial to apply to real-world settings
Which measure of disease frequency is best suited for research tracking men in the Framingham Study recently diagnosed with heart disease relative to person-years accrued?
Incidence Rate
What factors may impact the crude rates of populations being compared?
Gender, Race, Age
In the context of disease transmission, what distinguishes a vector from a fomite?
A vector is a living organism (such as an insect or tick) that transmits a pathogen, whereas a fomite is an inanimate object (such as clothing or a utensil)
What does the sensitivity of a screening test measure?
The probability that the test correctly classifies individuals who actually have the disease as positive (true positive rate)
Outbreak type characterized by "Prolonged exposure to the same source over an extended period of time."
Continuous Common Source Outbreak
Why do researchers prefer studying incidence rather than prevalence when investigating disease etiology?
Because exposure timing in regard to disease frequency can be determined with more precision
Out of 400 smokers, 23 develop lung cancer. In a group of 2,600 nonsmokers, 63 develop lung cancer. What is the interpretation of the risk difference?
There was an excess of 33.17 cases per 1,000 people of lung cancer in the smoking population.
Community immunity works well for a disease that has which core characteristics?
Disease spread by direct transmission, only one host, community interacting randomly, and disease/immunization conferring full protection.
What does the specificity of a screening test measure?
The probability that the test correctly classifies individuals who do not have the disease as negative (true negative rate).
Which subspecialty focuses specifically on the description and analysis of geographic variations in disease with respect to risk factors?
Spatial epidemiology
Number of deaths attributed to a specific cause / size of the population at the midpoint of a defined period of time. The fraction is usually expressed per 100,000 population.
Cause-specific mortality
What distinguishes absolute measurements from relative measurements of comparison in epidemiological studies?
Absolute measures show the excess risk or burden in a group (like risk difference), whereas relative measures show the strength of association (like relative risk) affecting assumptions about population impact
What type of transmission involves small particles transmitted through the air over time?
Airborne transmission
How does decreasing the cutoff threshold of a continuous screening test generally affect its sensitivity and specificity?
It increases sensitivity (catching more true positives) but decreases specificity (yielding more false positives).