Prospective Study

The term prospective study refers to a study design in which the documentation of the presence or absence of an exposure of interest is documented at a time period preceding the onset of the condition being studied. In epidemiology, such designs are often called cohort studies. Characteristic features of these designs include initial selection of study subjects at risk for a condition of interest, but free of disease at the outset. The occurrence/nonoccurrence of the condition is then assessed over a time period following recruitment. The time sequencing of the documentation of the exposure and outcome is an important feature and is related to a commonly cited form of evidence toward drawing causal inference about the relationship between the exposure and the outcome. The terms ...