The quality of being defensible, well-grounded or sound. In research, validity is the extent to which a test measures what it claims to measure.
Refers to what is assessed and how well this corresponds with the behaviour or construct to be assessed. In the case of ‘site validity’ it involves assessments that intend to assess the range of skills and knowledge that have been made available to learners in the classroom context or site. High ‘system validity’ involves assessments that intend to assess an often narrower range of skills and knowledge, deemed essential by the particular government body or system. Current validity theorising incorporates concerns about fairness and bias, and reflects similar understandings of the social basis of assessment. Validity is not simply the way in which a test functions, but depends on what it is used for and the interpretation and social consequences of the results. Thus, an essential part of validity is the concern with whether the inferences made from the results of an assessment are fair to all those who were assessed (Wyatt-Smith & Joy Cumming, 2009 in UNESCO-IBE, Glossary of Curriculum Terminology).