Answer: External validity
Step-by-step explanation:
External validity is the validity of applying the findings and conclusions derived from a study outside the context of that particular study. External validity is the degree to which the results of a scientific study can be generalized to other situations and across other situations, stimuli, people, and times.
External validity helps in answering the question of whether the research carried out can be applied to the real world. When the research is applicable to other settings, people and experiments, external validity is high otherwise it is low.
Chin-Hsing study may not be generalized to other schools or country shows that its external validity is low.