What threat to internal validity is most closely associated with a longitudinal design?
A) Instrumentation effects
B) Mortality effects
C) History effects
D) Selection bias

Question

Quizplus · Accepted Answer

Mortality effects, also known as attrition, are a significant threat to internal validity in longitudinal studies because participants may drop out over time, potentially biasing the results.

What Threat to Internal Validity Is Most Closely Associated with a Longitudinal