What is validity in assessment?
In assessment, validity refers to the correspondence between assessment results and student learning. Suppose that a means of assessment is designed to measure whether a student knows x. The means of assessment is valid if results indicate that the student knows x only when the student really does know x. Since it is impossible to know whether a student knows x without relying on some means of assessment, the only way to demonstrate that a means of assessment is valid is to compare its results with those from other means of assessment. If several means of assessment agree in indicating that the student knows x, it is likely that the student indeed knows x. In this way, one means of assessment serves to check the validity of another means. Hence the importance of using multiple means of assessment.
