An index that reflects the accuracy of selection associated with a predictive validity of "r" is presented. Based on Sheppard's thoerem on median dichotomies, it is a measure of improvement over chance assignment to "accept" (or "reject"). Because the index is a measure of the accuracy of this assignment, rather than…

DIMTEST is a statistical test procedure for assessing essential unidimensionality of binary test item responses. The test statistic T used for testing the null hypothesis of essential unidimensionality is a nonparametric statistic. That is, there is no particular parametric distribution assumed for the underlying ability distribution or for the…

A small data set is used to show that correlations and standard deviations measured within an explicitly selected group need not be smaller than those within an applicant population. Both validity and reliability estimates within a selected group can exceed those within an applicant population. (Author/LMO)

The purpose of this paper is to examine the validity of regression estimates when skewed dichotomous scales are used as independent variables. When Pearson product-moment correlations are used to measure zero-order associations involving dichotomous variables, the resulting coefficients underestimate the true associations. As a result, using…

A new approach to partialling components is used. Like conventional partialling, this approach orthogonalizes variables by partitioning the scores or observations. Unlike conventional partialling, it yields a common component and two unique components. (Author/GDC)

New tests for comparing the strength of association between a variable and each of two potential predictor variables are proposed and compared to an existing test in a simulation study. Recommendations for use are made. (Author/JKS)

Generally, this paper aims to: (1) provide clarification, quantification, and some mathematical analysis to the statistical problem of restricted range in a college admissions situation; and (2) discuss various questions related to the problem of selection strategies. (Author/PN)

The nature of the criterion (dependent) variable may play a useful role in structuring a list of classification/prediction problems. Such criteria are continuous in nature, binary dichotomous, or multichotomous. In this paper, discussion is limited to the continuous normally distributed criterion scenarios. For both cases, it is assumed that the…

The need for using invariance procedures to establish the external validity or generalizability of statistical results has been well documented. Invariance analysis is a tool that can be used to establish confidence in the replicability of research findings. Several approaches to invariance analysis are available that are broadly applicable across…

Intraclass correlation reliability estimates are based on the assumption that the various measures are equivalent. Joreskog's (1970) general model for the analysis of covariance structures can be used to test the validity of this assumption. (For related document, see TM 002 301.) (Author)

We are concerned with the hypothesis that two variables have a perfect disattenuated correlation, hence measure the same trait except for errors of measurement. This hypothesis is equivalent to saying, within the adopted model, that true scores of two psychological tests satisfy a linear relation. A statistical test of this hypothesis is derived…

A study to find valid indicators of the long-run effects of Comprehensive Employment and Training Act of 1973 (CETA) manpower programs that would meet prime sponsors' needs for short-term feedback indicated that the proxies being used were not strongly correlated with success in CETA programs. (MF)

The purpose of this study was to determine the validity of the American College Test (ACT) in predicting academic achievement of students from an area which is culturally, economically, and educationally depressed. The population, chosen from 6 community colleges serving the Appalachian region of Kentucky, consisted of 1,127 full time (12 or more…

This paper reports the results of an evaluative statistical analysis of the instrument employed for student evaluation of faculty at Oakton Community College (Illinois). The analysis was performed because the locally devised instrument had never been subjected to systematic study of reliability or validity, and because a review of pertinent…

The construct validity of four self-concept (SC) traits (general SC, academic SC, English SC, mathematics SC), as measured by three different scales (Likert, semantic differential, Guttman) for low- (n=252) and high-track (n=588) Canadian high school students, was assessed using both the Campbell-Fiske criteria, and a comparison of hierarchically…