Validity & Reliability

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Validity & Reliability by Mind Map: Validity & Reliability

1. Validity is when a test measures what it's supposed to.

2. Reliability happens when and if a test yields consistent results.

3. Test-Retest/ Stability

3.1. Test- retest or Stability is when a measure at two different times with no instruction in between will yield the same results. Ex: A math test is given on Friday to a group of 10 students, then given again on Monday. There is found to be correlation between the results of the 1st test and the 2nd test.

4. Equvialency

4.1. Equivalency reliability is the extent to which two items measure identical concepts at an identical level of difficulty. Equivalency reliability is determined by relating two sets of test scores to one another to highlight the degree of relationship or association.

5. Internal Consistency

5.1. Internal consistency is the extent to which tests or procedures assess the same characteristic, skill or quality. It is a measure of the precision between the observers or of the measuring instruments used in a study.

6. Criterion Validity

6.1. Is the measure consistent with what we already know and what we expect? Two subcategories: predictive and concurrent

6.1.1. Concurrent validity

6.1.1.1. Associated with pre-existing indicators; something that already measures the same concept

6.1.2. Predictive validity

6.1.2.1. Predicts a known association between the construct you’re measuring and something else.

7. Construct Validity

7.1. a test has construct validity if it accurately measures a theoretical, non-observable construct or trait. The construct validity of a test is worked out over a period of time on the basis of an accumulation of evidence. There are a number of ways to establish construct validity.

7.1.1. A test has convergent validity if it has a high correlation with another test that measures the same construct. By contrast, a test’s divergent validity is demonstrated through a low correlation with a test that measures a different construct.

7.1.2. we can asses the test’s internal consistency. That is, if a test has construct validity, scores on the individual test items should correlate highly with the total test score. This is evidence that the test is measuring a single construct

8. Content Validity

8.1. The extent to which a test adequately represents the subject-matter content or behavior to be measured -- commonly used in evaluating achievement or proficiency tests.

8.1.1. Example: a comprehensive math achievement test would lack content validity if good scores depended primarily on knowledge of English, or if it only had questions about one aspect of math (e.g., algebra)

9. If a test is unreliable, it cannot be valid. For a test to be valid, it must reliable. However, just because a test is reliable does not mean it will be valid. Reliability is a necessary but not sufficient condition for validity.