Measuring health and illness

“Epidemiology is the study (scientific, systematic, data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (patient is community, individuals viewed collectively), and the application of (since epidemiology is a discipline within public health) this study to the control of health problems.”¹ 

Basic descriptive epidemiology includes the ascertainment of the person, place and time:

• Who is getting the disease?  (i.e., “Person”)

–        sex; age; race/ethnicity; occupation

• Where is disease occurring?  (i.e., “Place”)

–        neighborhood (e.g., disease clusters); latitude (climate); urban vs. rural; national variations

• When did they get the disease?  (i.e., “Time”)

–        what season; what year (long-term trends)

–        elapsed time since exposure

• NOTE: this also called “person, place, & time”

Basic analytic epidemiology involves the ascertainment of causes and effect, or quantification of the association between the exposure and outcomes you are interested in and to test hypothesis about causal relationships.

This introductory module will focus on the (1) measures of disease frequency and (2) measures of association.