A bias is a flaw in either the study design or data analysis that leads to an erroneous result.

Case fatality rate is a mathematical quantity that describes the severity of a disease Y. Usually applied to acute diseases, it is the proportion of persons diagnosed with a disease Y who actually die [..]

A rate of disease is a measure of incidence or occurrence of disease in a population. The incidence rate is computed as follows:

This is the probability of an event given (or conditional upon) the occurrence of another event, e.g. the probability of disease Y given exposure to factor X.

Confounding is considered a "mixing of effects". When a factor X causes a disease Y, that relationship could be confounded by a factor C that is associated with both factor X and disease Y. [..]

A table (usually 2 rows and 2 columns) that is often used in epidemiology to show the relationship between disease and exposure. The table can be used to divide persons into the categories of diseased [..]

Risk can be thought of as a probability of developing disease given a set of circumstances. In epidemiology, we can calculate risks associated with various factors. We are often concerned about how we [..]

Disease transmission describes the process of spread of a disease agent through a population. Investigations of disease transmission answer the questions: Who got it? and How did it spread (either fro [..]

Many diseases have a baseline (endemic) incidence rate in the population, i.e. at any point in time some people are acquiring a given disease in the population, e.g. influenza (flu). An epidemic or ou [..]

Epidemiologists are bound by ethical guidelines that dictate justice and fairness in all aspects of their work. Epidemiologists must consider the fair and just treatment of their study subjects, as we [..]