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Validity defined…

Validity defined….

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Validity defined…

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  1. Validity defined… • In science and statistics, validity has no single agreed definition but generally refers to the extent to which a concept, conclusion or measurement is well-founded and corresponds accurately to the real world. The word "valid" is derived from the Latin validus, meaning strong. Validity of a measurement tool (i.e. test in education) is considered to be the degree to which the tool measures what it claims to measure. Wikipedia…

  2. Reliability and Validity • The Woodcock-Johnson III and the Cognitive Abilities Test (Form 6): A Concurrent Validity Study by David F. Lohman: University of Iowa March 2003 • For the WJ-III, we used standard scores in all analyses. Since these are normed to a mean of 100 and SD of 15 at each age, they can be used both for within- grade and across-grade analyses.

  3. Reliability • Reliability (Examine subtest percentages. Report subtest and scores that are lower than 80%.) • 1. Inter-rater (Did the author(s) or others evaluate inter-rater reliability? If they did, how and what were the results?) • 2. Internal consistency (Did the author(s) or others evaluate internal consistency? If they did, how and what were the results?) • 3. Test-Retest (Did the author (s) or others evaluate test-retest reliability? If they did, how and what were the results?)

  4. 1. Did the author or others evaluate inter-rater reliability? • The best conclusion seemed to be that the CogAT primarily measured something shared by the various WJ-III test clusters, and only secondarily abilities unique to each.

  5. 2. Internal consistency (Did the author (s) or others evaluate internal consistency? • Although the The Cognitive Abilities Test (CogAT) and the WJ-III are both based on hierarchical models of human abilities, • the CogAT focuses on general reasoning abilities, whereas • the WJ-III attempts to measure a much broader collection of stratum II abilities in Cattell-Horn-Carroll (CHC) theory.

  6. 3. Test-Retest Did the author(s) or others evaluate test-retest reliability? If they did, how and what were the results? • Yes - Three different types of inter-battery analyses are reported. First, we report correlations between the nine cluster scores on the WJ-III and the four CogAT scores. • Second, we report correlations between the broad group factors that were represented in our models of each battery. • Third, we report the results of a confirmatory, inter-battery factor analysis in which we estimate the correlation between the general factors on the two batteries.

  7. Lohman • To summarize, Lohman tested whether the covariances among the 13 WJ-III tests computed for our samples of second and fifth graders differed from covariances among these tests observed in the standardization for children of roughly the same age. • For second graders, we found congruence, but only after eliminating Gv from our model. This conforms with the hypothesis that abilities may exhibit a less differentiated structure for younger children.

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