Glossary of Epidemiology Terms

Intervention study: Epidemiologic study design that is experimental in nature and used to test a hypothesis about a cause-and-effect relationship.

Morbidity rate: A disease rate, specifically prevalence and incidence rates of diseases in a population in a specified time period.

Mortality rate: The number of deaths from all causes divided by the total population at a particular time and place.

Observational studies: Nonexperimental studies that describe, compare, and explain disease occurrence.

Prevalence: The total number of cases of the disease in the population at a given time divided by the number of individuals in the population.

Prevention:

Primary prevention: Inhibiting the development of disease before it occurs.

Secondary prevention: Also called "screening," refers to measures that detect disease before it is symptomatic.

Tertiary prevention: Focuses on people already affected by disease and attempt to reduce resultant disability and restore functionality.

Prospective study: An epidemiologic study design that assembles study groups before disease occurrence.

Random error: Is just that, random. It can occur during data collection (then called sampling error), coding, transfer, or analysis.

Relative risk: An epidemiologic measure of association that indicates the likelihood that an exposed group will develop a disease or condition relative to those not exposed.

Retrospective study: An epidemiologic study design that assembles study groups after disease occurrence.

Risk: The probability that an event, outcome, disease, or condition will develop in a specified time period.

Selection bias: The sampled group is biased in that it does not accurately represent the population it is intended to represent.

Sensitivity: The probability that an individual who has the disease of interest will have a positive screening test result. A test with high sensitivity has few false negatives, so you do not miss people with the disease.

Specificity: The probability that an individual who does not have the disease of interest will have a negative screening test result. A test with high specificity has few false positives so you do not identify people with no disease are rarely missed or told they don't have the disease.

• Diseased individuals with a positive screening test (true positives)
• Non diseased individuals with a positive screen (false positive)
• Diseased individuals with a negative screen ( false negative)
• Nondiseased individuals with a negative screen (true negative)

Systematic error: An error that is constant in a series of repetitions of the same experiment or observation. For example a scale could be set inaccurately.

Surveillance: The systematic collection and evaluation of all aspects of disease occurrence and spread, resulting in information that may be useful in the control of the disease.

Therapeutic trials: An epidemiologic intervention study design used to compare measures or interventions aimed at therapeutic benefits.

Validity: The validity of a study is dependent on the degree of systematic error. Validity is usually separated into two components:

Internal validity: Validity is dependent on the amount of error in measurements, including exposure, disease, and the associations between these variables.

External Validity: Means that the findings of the study can be accurately generalized to the population from which the sample was drawn (or even beyond that population to a more universal application).

 

---

You have reached the end of this section. If you wish to test your knowledge of
the subject matter, please visit: cisn-ecourse.org to take the corresponding e-Quiz -

"How Cancer is Studied"

For more information about our e-Training courses, please read the e-Quiz Introduction.

---