In epidemiology and statistics, an observational study draws inferences about the possible effect of a treatment on subjects, where the assignment of subjects into a treated group versus a control group is outside the control of the investigator. This is in contrast with experiments, such as randomized controlled trials, where each subject is randomly assigned to a treated group or a control group before the start of the treatment.
Read more about Observational Study: Reasons For Uncontrolled Experimentation, Degree of Usefulness and Reliability, Discussion
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“Oh, London is a man’s town, there’s power in the air;
And Paris is a woman’s town, with flowers in her hair;
And it’s sweet to dream in Venice, and it’s great to study Rome;
But when it comes to living, there is no place like home.”
—Henry Van Dyke (1852–1933)