Cronbach & Meehl Construct Validity in Psychological Tests

Validation of psychological tests has not yet been adequately conceptualized, as the APA Committee on psychological Tests learned when it undertook ( ) to specify what qualities should be investigated before a test is published. Page 281

Criterion-Oriented Validity Predictive ValidityConcurrent Validity

Criterion-Oriented Validity

Content Validity Hey, is this astronomy? Why are they talking about a universe?

In content validation, acceptance of the universe of content as defining the variable to be measured is essential.

Construct validity must be investigated whenever no criterion or universe of content is accepted as entirely adequate to define the quality to be measured. Determining what psychological constructs account for test performance is desirable for almost any test.

Thus, although the MMPI was originally established on the basis of empirical discrimination between patient groups and so-called normals (concurrent validity), continuing research has tried to provide a basis for describing the personality associated with each score pattern. Such interpretations permit the clinician to predict performance with respect to criteria which have not yet been employed in empirical validation studies

MMPI-2 now uses uniform T-scores

Use the Method of Contrasted Groups to create a Scale of Biological Sex (distinguishing the Boys from the Girls) Suppose our test has 30 items, Interpret a score of 10, 20, 30

Response Sets Social Desirability, positive impression management Yeah Saying, Acquiescence, directional bias (The Challenge of Response Sets) Response Scale Extremity, Extreme checking style (Ipsatization)

Jackson, D.N. & Messick, S.J. (1958) Content and style in personality measurement. Psychological Bulletin, 55, Rorer, L.G. (1965) The great response style myth. Psychological Bulletin, 63, Campbell, D.T. Siegman, C.R., & Rees, M.R. (1967) Direction of wording effects in the relationships between scales. Psychological Bulletin, 68, Block, J. (1965) The Challenge of Response Sets. NY: Appleton- Century-Crofts. Hamilton, D. (1968) Extreme Response Set, Psychological Bulletin, Psychological Bulletin, 69, PDF PDF

The Bender Visual Motor Gestalt Test or simply the Bender-Gestalt test is a psychological test first developed by child neuropsychiatrist Lauretta Bender. The test is used to evaluate "visual-motor maturity", to screen for developmental disorders, or to assess neurological function or brain damage.psychological testneuropsychiatristLauretta Bender

"If a new test is demonstrated to predict the scores on an older, well-established test, then an evaluation of the predictive power of the older test may be used for the new one." But accurate inferences are possible only if the two tests correlate so highly that there is negligible reliable variance in either test, independent of the other. Where the correspondence is less close, one must either retain all the separate variables operationally defined or embark on construct validation. Review worksheet on Bounds on Correlations

X Y Z

A VERY Brief Introduction to Factor Analysis

Common Factor V1 V2 V3 Observed Variables Unique Factors A VERY Brief Introduction to Factor Analysis

Specific Criteria Used Temporarily: The "Bootstraps" Effect Even when a test is constructed on the basis of a specific criterion, it may ultimately be judged to have greater construct validity than the criterion. We start with a vague concept which we associate with certain observations. We then discover empirically that these observations covary with some other observation which possesses greater reliability or is more intimately correlated with relevant experimental changes than is the original measure, or both.

Baron von Munchhausen Pull yourself up by your bootstraps "The Surprising Adventures of Baron Munchausen" (by Rudolph Erich Raspe, published in 1895) The real Baron Munchausen

Examples of the Bootstrap Effect Measurement of Temperature The Binet Simon Scale

EXPERIMENTATION TO INVESTIGATE CONSTRUCT VALIDITY Validation Procedures

Group differences. (Thurstone and Chave: Attitudes towards the church) Correlation matrices and factor analysis. Studies of internal structure.

Item-test correlations and certain reliability formulas describe internal consistency. It is unwise to list uninterpreted data of this sort under the heading "validity" in test manuals, as some authors have done. High internal consistency may lower validity. Only if the underlying theory of the trait being measured calls for high item intercorrelations do the correlations support construct validity. Negative item-test correlations may support construct validity, provided that the items with negative correlations are believed irrelevant to the postulated construct and serve as suppressor variables (31, p ; 44).

[,1] [,2] [,3] [1,] [2,] [3,] Correlations among predictor variables Suppressor Variables rxy = , ,

How do we calculate Standardized Regression weights?

Warning: Prepare to be Shocked! This is an extreme example. b = , ,

Y X2 X1 S

Studies of change over occasions. The stability of test scores ("retest reliability," Cattell's "N-technique") may be relevant to construct validation. Whether a high degree of stability is encouraging or discouraging for the proposed interpretation depends upon the theory defining the construct. N technique: The study of change over occasions

The Numerical Estimate of Construct Validity There is an understandable tendency to seek a "construct validity coefficient," A numerical statement of the degree of construct validity would be a statement of the proportion of the test score variance that is attributable to the construct variable.

If "creativity" is defined as something independent of knowledge, then a correlation of.40 between a presumed test of creativity and a test of arithmetic knowledge would indicate that at least 16 per cent of the reliable test variance is irrelevant to creativity as defined.