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
Famous quotes containing the word study:
“Daniel as a lad bought a handkerchief on which the Federal Constitution was printed; it is said that at intervals while working in the meadows around this house, he would retire to the shade of the elms and study the Constitution from his handkerchief.”
—For the State of New Hampshire, U.S. public relief program (1935-1943)