However, a major disadvantage of pre-experimental designs are their much lower validity than true experimental designs.
In a true experimental design, the researcher has total control over the experiment, including the who, what, when, where and how of it. Subjects are often assigned to conditions randomly. True experimental designs offer the strongest indications for causal effects of the independent variable because of the control and ability to account for impacting factors. True experimental designs come in a variety of forms. The most common design is the Pretest-Posttest Group Design with random
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