A studyAn investigation of a healthcare problem. There are different types of studies used to answer research questions, for example randomised controlled trials or observational studies. in which the researchers look at what happens over time to groups of people. They study changes or differences in one characteristic (e.g. whether or not people smoke) in relation to changes or differences in another characteristic (e.g. whether or not they get cancer).
Observational study by Selena Ryan-Vig
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