What does validity in measurement refer to?

Validity in measurement is fundamentally concerned with how accurately a tool or assessment measures what it is intended to measure. When we refer to the validity of an instrument, we are looking at whether it truly reflects the concept, trait, or behavior that it claims to assess. For example, if a test is designed to measure levels of dependence on alcohol, its validity would be judged based on whether it effectively captures the nuances of alcohol dependence, rather than measuring unrelated constructs.

The other options touch on important aspects of measurement as well but focus on different dimensions. Consistency of results over time relates to reliability, which ensures that repeated applications yield similar outcomes, while the ability to replicate results pertains to the test's stability across different populations and situations. Broad applicability suggests generalizability, which benefits from validity but does not inherently define it. Validity is specifically centered on the accuracy of the measurement related to the intended concepts.