validity

n. A statistical indicator of the extent to which a measure accurately reflects the target construct or phenomenon, or the extent to which logical conclusions can be drawn from the available data. In essence, validity examines whether a test, assessment, or study effectively measures what it was designed to measure. If a measure is valid, it is assumed that it is also reliable, although the converse is not true. While there are a number of types of validity, all emphasize various threats to the meaningfulness of the measurement and the conclusions drawn from it. – BJM