uTRAC - Frequently Asked Questions
an analytic study designed to determine the relationship between a condition and a characteristic shared by some members of a group. The population selected is healthy at the beginning of the study. Some of the members of the group share a particular characteristic, such as cigarette smoking. The researcher follows the population group over a period of time, noting the rate at which a condition, such as lung cancer, occurs in the smokers and in the nonsmokers. A prospective study may involve many variables or only two; it may seek to demonstrate a relationship that is an association or one that is causal. Prospective studies produce a direct measure of risk called the relative risk. Compareretrospective study.