Niels G. Waller

Types of dissociation and dissociative types: A taxometric analysis of dissociative experiences

This article examined evidence for dimensional and typological models of dissociation. The authors reviewed previous research with the Dissociative Experiences Scale (DES; E. B. Bernstein-Carlson & F. W. Putnam, 1986) and note that this scale, like other dissociation questionnaires, was developed to

Factor analysis and scale revision

This article reviews methodological issues that arise in the application of exploratory factor analysis (EFA) to scale revision and refinement. The authors begin by discussing how the appropriate use of EFA in scale revision is influenced by both the hierarchical nature of psychological constructs and the motivations underlying the revision. Then they specifically address (a) important issues that arise prior to data collection (e.g., selecting an appropriate sample), (b) technical aspects of factor analysis (e.g., determining the number of factors to retain), and (c) procedures used to evaluate the outcome of the scale revision (e.g., determining whether the new measure functions equivalently for different populations).

The prevalence and biometric structure of pathological dissociation in the general population : Taxometric and behavior genetic findings

Taxometric and biometric analyses were conducted on 2 North American samples to investigate the prevalence and biometric structure of pathological dissociation. Results indicated that approximately 3.3% of the general population belongs to a pathological dissociative taxon. A brief 8-item self-report scale called the DES-T can be used to calculate taxon membership probabilities in clinical and nonclinical samples of adults (a SAS scoring program is provided for this purpose). The genetic and environmental architecture of pathological dissociative symptoms was explored by conducting a biometric analysis on DES-T ratings from 280 identical and 148 fraternal twins. The findings suggest that approximately 45% of the observed variance on the DES-T can be attributed to shared environmental influences. The remaining variance is due to nonshared environmental influences.

Item Response Theory and Clinical Measurement

In this review, we examine studies that use item response theory (IRT) to explore the psychometric properties of clinical measures. Next, we consider how IRT has been used in clinical research for: scale linking, computerized adaptive testing, and differential item functioning analysis. Finally, we consider the scale properties of IRT trait scores. We conclude that there are notable differences between cognitive and clinical measures that have relevance for IRT modeling. Future research should be directed toward a better understanding of the metric of the latent trait and the psychological processes that lead to individual differences in item response behaviors.

Genetic and Environmental Influences on Religious Interests, Attitudes, and Values: A Study of Twins Reared Apart and Together

The role of genetic and environmental factors in the expression of religious interests, attitudes, and values was examined using data from adult twins reared apart and adult twins reared together. The Religious Values scale of the Allport-Vernon-Lindzey Study of Values, a Religious Interest scale from the Strong Campbell Interest Inventory, the Wiggins Religious Fundamentalism scale from the MMPI, a Leisure Time Religious Interest scale, and a second measure of Occupational Religious Interest were administered to 53 identical and 31 fraternal twin pairs who had been reared apart. The Leisure Time Religious Interest Scale and the second measure of Occupational Religious Interest were also administered to 458 identical and 363 fraternal twin pairs who had been reared together. Biometric model fitting indicated that approximately 50% of the observed variance of all five measures is genetically influenced.

The big seven model: a cross-cultural replication and further exploration of the basic dimensions of natural language trait descriptors

The objective of this study was to identify the major lexical dimensions in the Hebrew language and to compare these dimensions with the Big Seven factor structure. A list of 252 trait descriptors was assembled from a Hebrew dictionary, using nonrestrictive criteria similar to those introduced by A. Tellegen and N. G. Waller (1987). The factor structure recovered from these data largely replicates the Big Seven model. In particular, 2 major evaluative factors emerged, Positive and Negative Valence, which are prominent in the Big Seven but are not represented in the Big Five. Four of the remaining 5 factors also clearly correspond to 4 of the Big Seven dimensions and their counterparts in the Big Five.

The Tridimensional Personality Questionnaire : Structural validity and comparison with the Multidimensional Personality Questionnaire

Cloningers Tridimensional Personality Questionnaire (TPQ) is a self-report inventory designed to assess Novelty Seeking, Harm Avoidance, and Reward Dependence, the three primary dimensions of his Biosocial Learning Model of normal and abnormal personality. We examined the structural validity of the TPQ and the relations among the TPQ lower- and higher-order scales to those of the Multidimensional Personality Questionnaire (MPQ; Tellegen, 1982) in a sample of 1,236 adults. The factor structure of the TPQ was congruent with Cloningers predicted three-factor genotypic structure with one notable exception: the component scales of the Reward Dependence dimension share essentially no variance, and thus load on different factors. Both bivariate and multivariate analyses indicate that the TPQ and the MPQ share considerable variance, but that each inventory contains variance unpredicted by the other. In addition, the TPQ Harm Avoidance dimension appears to tap primarily a Negative Emotionality or neuroticism factor, rather than a disposition toward behavioral inhibition. These results support a number of Cloningers predictions concerning the structural and external validity of the TPQ, but also suggest that the TPQ may fail to adequately operationalize several components of his model.

Fitting the Two-Parameter Model to Personality Data

The Multidimensional Personality Questionnaire (MPQ; Tellegen, 1982) was parameterized using the two-parameter logistic item response model. This en tailed assessment of the suitability of personality data for item response analyses, including the assessment of dimensionality, monotonicity of item response, and data-model fit. The latter issue received special em phasis. Similarities and differences between maximum performance and typical performance data are dis cussed in relation to item response theory. Results suggest that the two-parameter model fits the MPQ data and that researchers engaged in the assessment of nor mal-range personality processes have much to gain from exploiting item response models. Index terms: item fit, item response theory, Multidimensional Per sonality Questionnaire, personality measurement, two- parameter model.

The Big Seven Factor Model of Personality Description: Evidence for Its Cross-Cultural Generality in a Spanish Sample

The discovery of the Big Seven factor model of natural language personality description (Tellegen, 1993 ; Tellegen & Waller, 1987 ; Waller in press ; Waller & Zavala, 1993) challenges the comprehensiveness of the Big Five factor structure. To establish the robustness and cross-cultural generalizability of the seven-factor model, a Big Seven (Tellegen, Grove & Waller, 1991) and a Big Five (John, Donahue, & Kentle, 1991) questionnaire were administered to 2 samples : (a) a sample of 569 community-dwelling volunteers from the United States and (b) a sample of 435 Spanish native speakers from Spain. Factor structures from the self- and peer-ratings on the Spanish version of the Big Seven questionnaire largely replicated the American structure (Waller, in press). Nevertheless, some psychologically meaningful item-level differences emerged. These differences suggest that Spaniards attach negative and positive values to self-other perceptions of introversion and unconventionality, respectively. Our findings support the cross-cultural robustness of the Big Seven factors and the advantages of this structure for studying culturally specific differences in personality traitterm evaluations.

Traitedness and the assessment of response pattern scalability

Scalability statistics are used to measure the degree to which an examinees item responses to a self-report measure conform to a specified pattern. This article proposes that a scalability index based on item response theory, called Z L , offers promise for detecting individual differences in traitedness. The Z L index is described and applied to data from 1,000 Ss who were administered the Multidimensional Personality Questionnaire (A. Tellegen, 1982). Low split-half reliabilities were found for Z L index scores computed within 11 personality scales. However, further data scrutiny revealed that valuable information about an individuals trait structure can still be gleaned from a scalability analysis