BIOS 1500 Lecture Notes - Lecture 9: Sound Bite, Type A And Type B Personality Theory, Odds Ratio
Document Summary
The case-control study is implemented using samples based on the dependent variable. It has backward directionality: arguing from knowing the dependent variable (disease) to assessing the independent (exposure status). The design consists of a sample of those with the disease (cases) , and at least one other sample of those without the disease (controls). The design fixes as known, the total sample size, and the marginal distribution for. Timing is retrospective, since both disease and exposure occurred in the past, prior to the study. The design is observational in that no interventions or randomization to treatments occurred. The design allows us to estimate: the marginal distribution of exposure. The two conditional distributions of exposure based on disease status. The design measures the prevalence of exposure in each group: cases, and controls. The prevalence of disease cannot be estimated as the sampling design pre-determined how many diseased (cases) and non-diseased (controls) were to be studied.
