The most significant threat to internal validity of the time series design is
A) history.
B) maturation.
C) regression.
D) mortality.

Question

Quizplus · Accepted Answer

History refers to any external events or factors that might affect the outcome of the study, but are unrelated to the intervention being studied. For example, if a new government policy is introduced during the study period that affects the outcome being measured, it could undermine the internal validity of the study. Maturation, regression, and mortality are also potential threats to internal validity in a time series design, but history is considered the most significant. Maturation refers to changes that occur naturally over time, such as physiological or psychological development in participants. Regression refers to statistical phenomenon in which extreme scores tend to move closer to the mean over time. Mortality refers to participant dropout, which can bias the sample and undermine the validity of the results.

The Most Significant Threat to Internal Validity of the Time