In the glossary of their book on testing, Alderson, Clapham, and Wall (1995) define validity as “the extent to which a test measures what it is intended to measure: it relates to the uses made of test scores and the ways in which test scores are interpreted, and is therefore always relative to test purpose” (p. 296). This definition needs to be modified when discussing the validity of an elicitation device instead of a test. Defining validity as the extent to which the device elicits what it is intended to elicit relative to the purpose of the elicitation device seems to be more appropriate here, and this statement will be adopted as a working definition of validity in this monograph. The modification of the definition of validity results in the fact that aspects of external validity, such as concurrent and predictive, cannot be employed. Since the tasks to be validated are elicitation devices, there are no valid and reliable data available about the tasks from other sources that could be used for concurrent validation. The same is true for predictive validity: there are no data about future performance that could serve as a basis of comparison. Conversely, measures of internal validity, such as face and content, and construct validity of the elicitation device could probably be examined, and they could contribute to the overall validity of the device.