POPM 3240 Lecture Notes - Lecture 17: Confounding, Medical Test
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No conclusion about associations between e and o. Main types include case reports, case series, and surveys. Compare between groups to explore associations between e ando. No control over allocation of subjects, no intervene. Observing natural occurrences and drawing conclusions based on these observations. Complete control over allocation of subjects (intervene) The differences between them is based on the selection of study subjects. Random sampling, not looking for certain exposure or outcome. E and o are assessed at the same time. Sample people that have the exposure and no exposure usually outcome-free. Selecting patient already with the outcome and track back in time for the exposure. Objective is to estimate prevalence and to assess whether the exposure is related to the outcome. Sampling without regard to the disease status or exposure status. Only a single point or a snapshot of the situation. Determine prevalence of e and o in population.