Retrospective Studies

**Definition:** Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.

**Tree numbers:** - E05.318.372.500.500.500 - E05.318.372.500.750.750 - N05.715.360.330.500.500.500 - N05.715.360.330.500.750.825 - N06.850.520.450.500.500.500 - N06.850.520.450.500.750.825

**Synonyms:** - Retrospective Study