The major threat to internal validity in the simple interrupted time series design is
A) history.
B) maturation.
C) selection.
D) additive effect of selection and history.

Question

Quizplus · Accepted Answer

The major threat to internal validity in the simple interrupted time series design is history, which refers to any event or occurrence that takes place during the study period other than the intervention itself that may affect the outcome being measured. Other threats to internal validity, such as maturation and selection, are less likely to be an issue in this design because the comparison is made within the same group over time. The additive effect of selection and history may also affect internal validity, but it is not the major threat in this design.

The Major Threat to Internal Validity in the Simple Interrupted