Posttest Only, Control Group

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Posttest Only, Control Group design looks a great deal like the Two Group, Ex Post Facto design, with the inclusion of random treatment.

R - Random assignment

slbl3.gif (530 bytes) Posttest Only, Control Group design does not use a pretest measure to establish a benchmark.
slbl3.gif (530 bytes) This is a two group design including an experimental group and a control group, where assignment to groups occurs through randomization. The experimental group is exposed to the manipulation; the control group is not.
slbl3.gif (530 bytes) There is no premeasurement - a measure of how conditions would have been if there was no manipulation. Both measures are taken after the manipulation occurred. There is no benchmark.
slbl3.gif (530 bytes) This design recognizes the threats associated with pretesting effect and pretest-manipulation interaction bias.

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Copyright Dr. Nancy D. Albers-Miller, All Rights Reserved