The pretest-posttest control group design, also called the pretest-posttest randomized experimental design, is a type of experiment where participants get randomly assigned to either receive an intervention (the treatment group) or not (the control group). The outcome of interest is measured 2 times, once before the treatment group gets the intervention — the pretest — and once after it — the posttest. Show
The objective is to measure the effect of the intervention which can be:
The pretest-posttest control group design has 3 major characteristics:
The pretest-posttest control group is the most commonly used design in randomized controlled trials. Advantages of the pretest-posttest control group designBy using a pretest, a control group, and random assignment, this design controls all internal threats to validity. Advantage of having a pretest measurementThis design is better than the posttest-only control group design because it adds a pretest. Adding a pretest:
Advantage of using random assignment and having a control groupRandom assignment and the control group will both limit the effects of:
Limitations of the pretest-posttest control group designParticipants included in any randomized study might not be typical people in the population i.e. they may not represent well the population of interest, this is because:
So the outcome of a randomized study may not generalize well to the population. More specifically, this design:
Example of a study that used the pretest-posttest control group designKoenig et al. used a pretest-posttest control group design to study the effect of a yoga program on the classroom behavior of autistic children. These children were randomly assigned to either receive the yoga program or their standard morning routine. The study concluded that yoga can significantly improve the classroom behavior of autistic children. But because the researchers used a convenience sample from a particular school and the classrooms that were allowed to participate were hand-picked by administrators, the study outcome may not generalize well to all children with autism. What is a pretest posttest control group design example?Example: All students in a certain class take a pre-test. The teacher then uses a certain teaching technique for one week and administers a post-test of similar difficulty. She then analyzes the differences between the pre-test and post-test scores to see if the teaching technique had a significant effect on scores.
What is a pretest posttest control group design?The pretest-posttest control group design, also called the pretest-posttest randomized experimental design, is a type of experiment where participants get randomly assigned to either receive an intervention (the treatment group) or not (the control group).
Which of the following is an example of a oneWhich of the following is an example of a one-group pretest-posttest quasi-experimental research design? A researcher records exam scores before and following a new lecture.
What is pretest and posttest experimental design?a research design in which the same assessment measures are given to participants both before and after they have received a treatment or been exposed to a condition, with such measures used to determine if there are any changes that could be attributed to the treatment or condition.
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