The one-group posttest-only design should be avoided because
A) All experimental designs have to have more than one group
B) There are many uncontrolled threats to validity
C) It produces unreliable results
D) It will not be possible to code the data

Question

Quizplus · Accepted Answer

The one-group posttest-only design should be avoided because there are many uncontrolled threats to validity. Without a comparison group, it is impossible to determine if any observed changes are due to the intervention or other factors such as history, maturation, or testing. This lack of control for external factors reduces the internal validity of the study.

The One-Group Posttest-Only Design Should Be Avoided Because