Face validity is not always seen as validity in the technical sense, however. Besides these issues, and the lack of teacher training, the issues of time and cost in implementation of performance assessment, and the difficulties of consensus in grading this form of assessment have been broached. In traditional measurement, the most important identifier of a test is the validations of the results of the test. Face validity states that if something appears to be the behavior that you are attempting to measure. This is not considered scientifically sound by measurement people.
Content validity is easier to defend in an instrument.
Most traditional texts state that one should be sure that the test measures what it is intending to measure. The classroom teacher needs to know and understand reliability to create, use, and interpret performance-based assessment. This is difficult because this type of assessment relies heavily on inter-rater agreement and limited sampling. Heavily used by norm-reference test makers, reliability allows the test scores to spread out. Dr. Dan all rights reserved.