Browsing by Author "Helmes, Edward"

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    Basic structure content scaling
    (1979) Jackson, Douglas N.; Helmes, Edward
    A basic structure approach is proposed for obtaining multidimensional scale values for attitude, achievement, or personality items from response data. Based on conventional components analysis, and described in terms of singular value or Eckart-Young decomposition of a data matrix, basic structure scaling yields projections of items upon axes in the person space, equivalent to obtaining component scores for items, with component loadings associated with individuals. Unlike multidimensional scaling methods, the scaling of large sets of stimuli is practical and judgments of items are obviated. In attitude and personality item scaling, the technique permits the unconfounding of scale values due to response bias and to content. It also permits the partitioning of item indices of popularity or difficulty among a number of relevant dimensions, a property of possible relevance to tailored or adaptive testing.
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    The item factor structure of the Personality Research Form
    (1977) Helmes, Edward; Jackson, Douglas N.
    Multiscale personality inventories have rarely, if ever, demonstrated factor structure broadly consistent at the item level with scale keys. An item factor analysis of the 352 items of PRF-E was undertaken to evaluate the extent to which PRF items define separate and distinct factors corresponding to keyed scales. A matrix based on 352 items and 214 subjects drawn from 31 colleges was decomposed according to the Eckart-Young theorem, the factor loading matrix was formed, and then was rotated to an orthogonal target matrix of the 22 PRF-E scales. Inspection of the rotated matrix showed that only 2 of the 352 items failed to load in the keyed direction. The mean loading of items on their scale factor was .38; the mean loading of non-scale items was .09. This strong tendency for scale items to load more highly than non-scale items was also reflected in the majority of scale items being among the 16 highest loadings on each scale factor. For three scales, Dominance, Harmavoidance, and Order, the scale items were the 16 highest loaded items. The observed item factor structure of the PRF is interpreted as being attributable to the methods of construct definition and item selection used in the construction of the PRF.
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    A psychometric investigation of the Eysenck Personality Questionnaire
    (1980) Helmes, Edward
    Summaries of item properties for the Eysenck Personality Questionnaire (EPQ) are reported, based upon the responses of 99 male and 92 female undergraduate psychology students. Means, standard deviations, and internal consistencies were comparable to those already published, with the exception of lower reliabilities for the P and L scales. A high incidence of extreme p values and correlation with social desirability was noted for the P scale. Item factor analyses at both the first- and third-order levels did not replicate the four-factor structure claimed by Eysenck; at best, four components accounted for approximately 30% of the observed variance. Many items did not load in accordance with the EPQ scoring key, and many items did not load on an interpretable component. The question of difficulty factors is discussed: None were located. It is concluded that there is little empirical support for the structure claimed for the EPQ.