Why do repeated measures improve internal validity in a single-case experiment?

Question

Quizplus · Accepted Answer

Repeated measures improve internal validity in a single-case experiment by providing a more reliable measure of behavior both before and after treatment. This is because multiple measurements of the same behavior are taken, which helps to reduce the impact of extraneous variables and increases the accuracy of the data. This, in turn, improves the internal validity of the results. Choices A, B, and D do not directly relate to how repeated measures improve internal validity in a single-case experiment.

Why Do Repeated Measures Improve Internal Validity in a Single-Case