Background: Validity is a core topic in educational and psychological assessment. Although there are many available resources describing the concept of validity, sources of validity evidence, and suggestions about how to obtain validity evidence; there is little guidance providing specific instructions for planning and carrying out validation studies.
Method: In this paper we describe (a) the fundamental principles underlying test validity, (b) the process of validation, and (c) practical guidance for practitioners to plan and carry out sufficient validity research to support the use of a test for its intended purposes.
Results: We first define validity, describe sources of validity evidence, and provide examples where each of these sources are addressed. Then, we describe a validation agenda describing steps and tasks for planning and developing validation studies.
Conclusions: Finally, we discuss the importance of addressing validation studies from a comprehensive approach.