Reliability and Validity Matrix Essay Example

stable over time (Cohen & Swerdlik, 2010). This is because test/retest reliability is based on taking the same test, with the same people, at two different times. If the construct being measured is purported to change over time, then the scores of the test would vary because of true variance, rather than error variance—which is the basis of reliability, the latter that is. An example of this principle might be an achievement test measuring grammatical skills.

If the test-taker undergoes a series of lessons on grammar between the first test and the second test, then the test will show variance, but not due to error but due to the intermediary variable of education. Test/retest reliability would be inappropriate in this situation. The strength of this measurement of reliability are in tests that, “…employ outcome measures such as reaction time or perceptual judgment” (Cohen & Swerdlik, 2010, p. 143). This is because these types of psychometric traits do not vary greatly over time and are not sensitive to many types of intervening variable. The weakness of test/retest reliability is, of course, that the underlying constructs being tested can change over time, and therefore lower the test/retest reliability due to true variance rather than error variance. In this case, the overall reliability of a test might be seen as lower even though the actual measurement of the construct is stable (it is just that the construct itself varies). | Parallel and alternate forms| Both parallel and alternative forms of test reliability utilize multiple instances of the same test items at two different times with the same participants (Cohen & Swerdlik, 2010).

These types of measures of

reliability would be most appropriate with tests that measure traits that are stable over a long period of time and inappropriate when measuring finite emotional states or anxiety levels. | The strength of this measure of reliability is that it measures the core construct through several variances of the same test item. If equivalent scores are found on multiple forms of the same test item, then the reliability of the test will go up. Moreover, there are ways to perform this type of reliability analysis without having the test-taker undergo multiple examinations: internal onsistency estimate of reliability. This type of analysis would save time and money. | Designing these types of measures are time-consuming, expensive, and tiresome for the test-taker who has to take variations of the same test items over and over again. Also, these forms of testing reliability are not dependable for measuring constructs that change over time, such as anxiety levels. Another weakness is that if the tests are taken some time apart, then intervening variables might have an effect on the scores, thereby increasing error variance.

A good example might be the inkblot test. Psychologists that adhere to the psychodynamic perspective of psychopathology would say that the test is perfectly valid for determining personality characteristics, but the test taker might not understanding how the test applies to personality development, thereby undermining the face validity of the test.

For instance, a final course exam should test the content area that the course covered. Further, this measure might not be applicable in situations where the skills that the test designer are looking for in the applicant are not currently part of

the skill-set of the already employed, such as in cases of new positions. One of the strengths of content validity is that it can used to work backwards from job responsibilities to job applicant requirements.

First, the test designer would examine veteran workers perform their job, and then design an application process that looks for these qualities in a potential employee. The items that are judge essential for the job are the ones that are most advantageous for the applicant to possess. The downfall of content validity is that the perspective of the material being covered is culturally and chronologically subjective, meaning that the questions can have different answers in different areas of the world or at different times.

I suppose this measure of validity might not be appropriate in situations where there is not one clear construct that is being measured, such as generalized achievement tests. | One of the main strengths of construct validity is that the procedures used to verify underlying constructs follow the edicts of the scientific method. A hypothesis is formulated, predicting that if someone possesses in great quantity the construct of intelligences—as verified through other measures—then they will score high on a test purporting to measure intelligence.