a group of people with a common characteristic in terms of person, place and time
*Fixed- membership based on an event which is permanent
*Transient-membership based on a condition that can change - ANS-Population
A measure concerned with the strength of the relationship between variables, (r) is the
coefficient statistics.... -1<r<+1 - ANS-Correlation
A study in which a representative cross section of the population is tested or surveyed at one
specific time. Think "snapshot" ! Measure: Prevalence of Disease/Odds Ratio, Cons: Can not
determine cause and effect - ANS-cross-sectional study
a study in which the units of analysis are populations or groups of people rather than individuals
*Exposure Status: based on the population
Con: Ecological Fallacy: makes assumptions about the individual based on finding at the level of
the population - ANS-Ecological Study
A type of epidemiologic study where a group of individuals with the diseases, referred to as
cases, are compared to individuals without the disease, referred to as controls (sampling based
on outcome)...Disease is rare, has a long induction period and little is known about the disease -
ANS-Case-Control Study
fulfill society interest in assuring conditions in which people can be healthy - ANS-Mission of
Public Health
refers to how well the outcome of a study can be expected to apply to other settings -
ANS-External Validity
The odds that an individual with a prognostic (risk) factor had an outcome of interest as
compared to the odds for an individual without the prognostic (risk) factor.... AD/BC.... odds in
exposed/odds in unexposed - ANS-Odds Ratio (OR)
The ratio of the incidence rate of a disease or health outcome in an exposed group to the
incidence rate of the disease or condition in a non-exposed group..... A/(A+B)/ C/(C+D)... often
used in cohort studies - ANS-Relative Risk (RR)
used to predict or estimate the value of one variable corresponding to a given value of another
variable - ANS-Regression