Validity and Reliablity

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Validity and Reliablity by Mind Map: Validity and Reliablity

1. Reliability: the consistency with which a test yields the same rank for individuals who take the test more than once (p. 338).

1.1. Test-Retest: a method of estimating reliability. A test is given twice and the correlation between the first set of first set of scores and the second set of scores is determined.

1.1.1. **The main problem with Test-Retest is that some form of memory or experience is involved when the test is taken the second time.

1.1.2. The interval between testing must be considered: the longer the interval between tests, the less reliable the test results will be.

1.2. Alternate Forms (Equivalence): a method of using two forms of a test to obtain an estimate of the reliability of the scores of a test.

1.2.1. Both forms of a test are given to students and the correlation between the two sets of scores is determined.

1.3. Internal Consistency: a method of ensuring that items in a test are correlated. *If a student does well on one item, then he or she should do well on other, similar items*

1.3.1. Split halves: the process of splitting a test into two equal halves and finding the correlation between the two.

1.3.1.1. **Only works when items of different levels of difficulty are randomly spread throughout a test**

1.3.2. Odd-Even Reliability: test items are divided into two halves by placing all odd-numbered items into one half and all even-numbered items into the other half.

2. Validity: achieved when a test measures what it's supposed to measure (P. 326).

2.1. Content Validity: Established by inspecting test questions to see whether or not they match learning objectives.

2.1.1. **Easy to see in achievement tests, but difficult to see in personality or aptitude tests**

2.1.2. Gives information about whether a test looks valid, but does not indicate whether the reading level is too high or if items are poorly written.

2.2. Criterion-Related: a method of correlating scores from a test with an extreme criterion.

2.2.1. Concurrent--deals with measures that can be given at the same time as the original measure to be validated. **A test developer who designs a short screening test that measures IQ might show that the test is highly correlated with the Binet IV and establish concurrent-related validity evidence for the test**

2.2.2. Yields a numeric value (a correlation coefficient) called a validity coefficient.

2.2.3. Is determined by giving the new test and the established test to test-takers then finding correlation between the two sets of scores.

2.3. Construct Validity: used if a test is being created to measure something not previously measures, or not measured well, and no criterion exists to compare the test to.

2.3.1. **A test has construct validity if its relationship to other information corresponds well with some theory**

2.3.2. Any information that shows whether results from a test correspond to what is expected says something about the construct validity evidence for that test.

3. Validity and Reliability are important because assessment shows skills and information learned. Without valid, reliable tests, test scores may not accurately reflect skills and content mastery.

4. Validity and Reliability help educators make important decisions about placement, promotion, instructional methods, differentiated instruction, and special services.

5. Validity and reliability help tests align with state and Common Core standards.