The comparison of individuals with a certain illness to similar healthy individuals, matched by age, sex or other factors in order to define risk factors for the illness.
A study in which diseased and non-diseased groups are compared with respect to past exposures or other characteristics
A scientific study that compares a group of people with disease (such as leukemia) to a similar group of people without that disease. This type of study compares the levels of exposure (radiation or chemical) each group had before appearance of the disease.
A study in which people with a disease (cases) are compared to people without the disease (controls) to see if their past exposures to chemicals or other risk factors were different.
In a case control study, two groups are contrasted: the subjects in one share a characteristic, usually a disease (the cases), and the subjects in the other do not (the control group). See also Control group.
A study which starts with the identification of persons with the disease of interest and a suitable control group of persons without the disease. The relationship of an attribute to the disease is examined by comparing the diseased and non-diseased with regard to how frequently the attribute is present or, if quantitative the levels of the attribute, in each of the groups. Case control studies are sometimes called "retrospective studies." In relation to gastrointestinal illness they are usually undertaken to test a hypothesis that a certain type of food caused the illness to occur by comparing the ill (cases) with well people (controls). Controls are usually matched with the cases for sex, age and postcodes.
Involves identifying patients who have the outcome of interest (cases) and control patients without the same outcome, and looking back to see if they had the exposure of interest.