What does the term 'validity' refer to in the context of testing?

In the context of testing, 'validity' is fundamentally about the extent to which a test measures what it claims to measure. This means that a valid test accurately assesses the specific skills, knowledge, or abilities it is intended to evaluate. For example, if a language proficiency test is designed to measure reading comprehension, validity ensures that the test actually evaluates that skill rather than unrelated areas.

Validity is essential because it determines the usefulness and effectiveness of the test results, impacting decisions made based on those results, such as placement in educational settings or program evaluation. Other aspects of test quality, like reliability and fairness, while important, do not capture the essence of validity, which centers on the alignment between the test's purpose and its actual measurement.