Validity asks if the test is measuring the data it was intended to measure.作者：Lucinda Cedeno
1. Content validity: ensures that the test is covering the specific material it was intended to test.
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2. Criterion-related validity evidence:scores from a test correlate with an eternal criterion. There are two types- concurrent evidence determines a numeric values and predictive evidence will tell us how well the student will due on other settings.
3. Construct validity- the test results corresponds to a theory.
