What is a pretest-posttest design?
From PsychWiki - A Collaborative Psychology Wiki
A pretest-posttest design is used in many true experimental designs because it administers a pretest before the experimental manipulation and a posttest, which is the same test as the pretest, after the manipulation. A pretest-posttest design is usually the preferred method used in true experimental designs to measure change and compare participant groups because it allows the administrator to assess the effect of the experimental manipulation by looking at the difference between the pretest and posttest.
Example / Application
Example: Pretest-posttest design explanation
Application: In this video on the pretest-posttest design, the experimental value of this method is described. It is explained that the tutor administers a pretest to the children to assess their skill level in a particular subject, then teaches them for a week and administers a posttest, the same as the pretest, in order to assess the effect of the tutoring. If the scores of the posttest improved from the scores on the pretest, one could conclude that the improvement was due to the tutoring.