Question

What is the main analytical difference in the two designs? ​ Prospective vs. Retrospective Study Design with examples please.

Answer 1

In Prospective Study Design, the investigators design the study, recruit subjects and collect data on all subjects before any of the subjects have developed any of the outcomes of interest. The subjects are then followed into the future in order to record the development of any of the outcomes of interest.

Example: For investigating the effect of smoking habits affect young drivers, investigators enroll volunteer truck drivers, collect baseline exposure information hat none of the subjects have developed any of the outcomes of interest. The subjects are followed longitudinally over a period of time to determine i and when they become diseased and whether their exposure status changes outcomes.

In Retrospective Study Design, the investigators collect and evaluate materials that are existing at the time the research is conceived.

Example: For investigating effect of smoking by female nurses, data is collected on female nurses who smoke and ones who do not smoke in terms of a particular outcome such as lung cancer. Data on the relevant events for each individual, the form and time of exposure to a factor and the time of subsequent occurrence of the outcome are collected from the existing records and analyzed.to determine the relative risk of the cohort compared to the control group.