Some Practical Considerations Around Epidemiologic Studies
Epidemiologic studies need to be carefully planned beforehand. This is true for any kind of study, be it a simple sample survey, a study of one of the types defined in Lesson 15, or a community study. The plan for the study, which is also called the “study protocol”, must cover all its aspects and stages. A classical mistake that is still being made from time to time consists in saying: “Let us collect the data first, and then start thinking about how to analyze them”. The team of investigators has to define not only the data collection but also the core methods of analysis and evaluation before starting the study; they are part of the study plan. This does not exclude another look at the data after the study from a different angle, for example when they seem to point to something unexpected.