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List the six specific threats to internal validity that can be effectively ruled out by adding a control group to a pretest-posttest design. In addition, describe how the control group is treated in comparison to the treatment group.
Question: List the six specific threats to internal validity that can be effectively ruled out by adding a control group to a pretest-posttest design. In addition, describe how the control group is treated in comparison to the treatment group.
Sample answer: The six threats to internal validity are history, maturation, testing, instrumentation, regression to the mean, and spontaneous remission. The control group does not receive the experimental treatment but is subjected to the same external events, passage of time, and repeated measurements as the treatment group.
Key points:
- Identifies history, maturation, testing, instrumentation, regression to the mean, and spontaneous remission as the six threats.
- States the control group does not receive the experimental treatment.
- States the control group experiences the same external events, passage of time, and repeated measurements as the treatment group.
Rubric: To earn full credit, the student must: 1) Identify history, maturation, testing, instrumentation, regression to the mean, and spontaneous remission. 2) Specify that the control group does not receive the experimental treatment. 3) State that the control group is subjected to the same external events, passage of time, and repeated measurements.
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Research Methods in Psychology - 4th American Edition @ KPU
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To properly rule out threats to internal validity in a pretest-posttest design, the control group must be shielded from the external events and passage of time experienced by the treatment group.
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List the six specific threats to internal validity that can be effectively ruled out by adding a control group to a pretest-posttest design. In addition, describe how the control group is treated in comparison to the treatment group.
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A school psychologist tests a new reading app. The treatment group (using the app) improves their reading speed by words per minute from pretest to posttest, while the control group (using standard books) also improves by words per minute. Apply your understanding of pretest-posttest control group designs to state the conclusion the psychologist should draw about the app's effectiveness and why.