SPH 300 Module 2: Epidemiology Measures of Disease Frequency

Comprehensive vocabulary flashcards covering basic measures of disease frequency, association, diagnostic test characteristics, and common epidemiological study concepts from Module 2.

Association

A statistical relationship between two variables indicating they tend to occur together, without implying that one causes the other.

Causation

A relationship where one variable directly influences or causes a change in another, establishing a cause-and-effect link.

Ratio

The relative magnitude of two quantities or a comparison of two values where the numerator and denominator do not have to be related.

Proportion

A specific type of ratio that compares a part to the whole, where the numerator is always included in the denominator; bounded between 0 and 1.

Percentage

A way to express a proportion as a fraction of 100, used to compare parts of a whole across different group sizes.

Probability

The likelihood of an event occurring, expressed on a scale from 0 (impossible) to 1 (certain).

Prevalence

The proportion of a population with a specific condition or disease (including both new and pre-existing cases) at a particular point in time.

Snapshot

A term often used to describe prevalence because it represents the burden of disease at one specific point in time, typically in cross-sectional studies.

Incidence (Rate)

The occurrence of new cases of a disease or condition in a population over a specified period of time.

Cumulative Incidence

Also known as incidence proportion, it is the probability of developing a disease over a stated period of time for a population initially free of the disease.

Numerator

The top number of a fraction, representing the cases or items being counted.

Denominator

The bottom number of a fraction, representing the total population or person-time being studied.

Person-years

The total amount of time that individuals in a study contribute while they are at risk of incurring the outcome of interest.

Prevalence Pool

A visual concept showing how prevalence is increased by incident/recurring cases and decreased by recovery, remission, or mortality.

Risk

The probability of an occurrence of an event or outcome during a specified period.

Risk Ratio

A measure of association calculated as the ratio of the risk in an exposed group to the risk in an unexposed group.

Odds Ratio

A measure of association calculated as the ratio of the odds of an event in an exposed group to the odds in an unexposed group.

Sensitivity

The probability that a person with the outcome of interest is correctly identified as positive by a diagnostic test.

Specificity

The probability that a person without the outcome of interest is correctly identified as negative by a diagnostic test.

False Negative

A diagnostic result that incorrectly labels a diseased person as healthy (negative).

False Positive

A diagnostic result that incorrectly labels a healthy person as diseased (positive).

True Positive

A person with the outcome of interest who is correctly identified as positive by a test.

True Negative

A person without the outcome of interest who is correctly identified as negative by a test.

Null Hypothesis

The statistical assumption that there is no association between variables or that differences observed occur due to chance alone.

P-value

The probability that the observed difference between groups is due to chance alone.

Confidence Interval

A range of values within which a measured parameter is expected to fall a certain percentage of the time (usually 95%) if the population is sampled repeatedly.

Bias

The systematic deviation of results or inferences from the truth caused by the collection, analysis, or interpretation of data.

Confounding

The distortion of the association between an exposure and outcome by a third variable related to both.

Effect Modification (Interaction)

Variation in the effect of a study factor across different levels of another factor.