Answer:
internal validity
Explanation:
There are two different types of validity i.e, internal and external validity and is described as the phenomenon that generally represents the meaningfulness and trustworthiness of the result of a particular study or research.
Internal validity: In statistics and research methods, the term internal validity is determined as the process that involves the degree of wellness to which a particular study is being done significantly if it avoids or ignores the confounding or not. Hence, if in a particular study the chance of confounding is less then the internal validity will be high i.e, they are inversely proportional to each other.
In the question above, the given statement signifies that internal validity is being threatened.
