Some uniqueness results for PARAFAC2

Whereas the unique axes properties of PARAFAC1 have been examined extensively, little is known about uniqueness properties for the PARAFAC2 model for covariance matrices. This paper is concerned with uniqueness in the rank two case of PARAFAC2. For this case, Harshman and Lundy have recently shown, subject to mild assumptions, that PARAFAC2 is unique when five (covariance) matrices are analyzed. In the present paper, this result is sharpened. PARAFAC2 is shown to be usually unique with four matrices. With three matrices it is not unique unless a certain additional assumption is introduced. If, for instance, the diagonal matrices of weights are constrained to be non-negative, three matrices are enough to have uniqueness in the rank two case of PARAFAC2. The authors are obliged to Richard Harshman for stimulating this research, and to the Associate Editor and reviewers for suggesting major improvements in the presentation.     

Factor structure of the basic personality inventory with incarcerated offenders

The item and scale factor structure of the Basic Personality Inventory (BPI) was examined in a sample of 486 offenders incarcerated for violent and sexual crimes. Separate principal-component analyses of the items for each of the 11 clinical scales, critical item scale, and social desirability scale indicated a one-dimensional factor solution for all scales except Depression and Persecutory Ideation. The Depression scale's two factors were Hopelessness and Depressive Affect and the Persecutory Ideation scale's two factors were General Paranoia and Perception of External Control. Although the factors for these two scales may assist in interpretation, the correlations between the factors and the total score of their respective scale were high. Confirmatory factor analysis of the 220 items from the 11 clinical scales supported the factorial logic of the scoring key. Analysis of the 11 clinical scales resulted in two factors: General Psychopathology/Adjustment and Antisocial Orientation. The results suggest that all but two scales can be viewed as unidimensional thereby allowing for a straightforward clinical interpretation. These analyses support the internal structure of the BPI and lend credence to external validity work with forensic populations.     

Accounting for Poverty: From Attribution to Discourse

In this article it is argued that the attributional literature concerning explanations of poverty is inadequate due to its theoretical presuppositions. It is proposed that a discursive approach is better able to withstand criticism and contribute to a more adequate understanding of poverty accounts. Some examples are given of how a discursive approach might work in practice.     

A nonparametric approach for assessing latent trait unidimensionality

Assuming a nonparametric family of item response theory models, a theory-based procedure for testing the hypothesis of unidimensionality of the latent space is proposed. The asymptotic distribution of the test statistic is derived assuming unidimensionality, thereby establishing an asymptotically valid statistical test of the unidimensionality of the latent trait. Based upon a new notion of dimensionality, the test is shown to have asymptotic power 1. A 6300 trial Monte Carlo study using published item parameter estimates of widely used standardized tests indicates conservative adherence to the nominal level of significance and statistical power averaging 81 out of 100 rejections for examinee sample sizes and psychological test lengths often incurred in practice.The referees' comments were remarkably detailed and greatly enhanced the writeup and sensitized the author to certain pertinent issues. Discussions with Fritz Drasgow, Lloyd Humphreys, Dennis Jennings, Brian Junker, Robert Linn, Ratna Nandakumar, and Robin Shealy were also very useful.This research was supported by the Office of Naval Research under grant N00014-84-K-0186; NR 150-533, and by the National Science Foundation under grant DMS 85-03321.     

A genetic two-factor model of the covariation among a subset of Multidimensional Aptitude Battery and Wechsler Adult Intelligence Scale—Revised subtests

The phenotypic and genetic factor structure of performance on five Multidimensional Aptitude Battery (MAB) subtests and one Wechsler Adult Intelligence Scale—Revised (WAIS-R) subtest was explored in 390 adolescent twin pairs (184 monozygotic [MZ]; 206 dizygotic (DZ)). The temporal stability of these measures was derived from a subsample of 49 twin pairs, with test–retest correlations ranging from .67 to .85. A phenotypic factor model, in which performance and verbal factors were correlated, provided a good fit to the data. Genetic modeling was based on the phenotypic factor structure, but also took into account the additive genetic (A), common environmental (C), and unique environmental (E) parameters derived from a fully saturated ACE model. The best fitting model was characterized by a genetic correlated two-factor structure with specific effects, a general common environmental factor, and overlapping unique environmental effects. Results are compared to multivariate genetic models reported in children and adults, with the most notable difference being the growing importance of common genes influencing diverse abilities in adolescence.     

认知需要与战略决策过程之间的关系

认知需要指人们在信息加工过程中是否愿意投入周密的心考以及能否从深入的思考中获得享受．它反映的是人的认知动机。由于企业管理者在决策过程中涉及诸多处理信息和思考问题的环节,认知需要必然在这一过程中起作用。本研究运用情境案例法探讨了在不确定环境下决策者的认知需要与其在战略决策过程中分析环境和判断战略导向的关系。通过相关分析发现高认知需要者在决策过程中更倾向于关注环境、对环境做出积极判断、强调从长远和全面的角度去分析企业战略。     

Validation of the Multidimensional Blood/Injury Phobia Inventory: Evidence for a Unitary Construct

The Multidimensional Blood/Injury Phobia Inventory (MBPI) was developed from a theoretical framework to characterize a broad range of feared stimuli and phobic reactions associated with this pathology. The MBPI consists of 40 items that cross 4 types of stimulus content (injections, hospitals, blood, injury), 5 types of phobic responses (fear, avoidance, worry, fainting, disgust), and a self versus other focus. This study reports on administration of the MBPI to 558 undergraduates, 9 of whom had blood/injury phobia. The instrument had a Cronbach's alpha of .91 and demonstrated good concurrent validity, convergent validity, and discriminant validity. One large factor emerged in an unrotated principal components analysis, suggesting that blood/injury phobia is a unitary psychometric construct. Exploratory factor analyses revealed a 6-factor solution defined by stimulus content domains and fainting, each of which may be important to consider clinically when assessing the unique concerns of treatment-seeking individuals.     

Path analytic examination of a cognitive model of PTSD

Ehlers and Clark (2000) developed a cognitive model of posttraumatic stress disorder (PTSD) symptom maintenance which implicated the role of posttraumatic cognitions and aspects of the trauma memory in maintaining symptoms via an increased sense of current threat. The aim of the current study was to empirically test a variant of this model using path analysis. Participants in the current study were 514 undergraduates at a midwestern university who reported experiencing at least one traumatic event. Path analyses examined various models of the possible relationships between one’s posttraumatic cognitions and the centrality of the traumatic event to the sense of self (considered an aspect of memory integration) in predicting current level of PTSD symptoms. Results indicate that both event centrality and posttraumatic cognitions are unique and independent predictors of current symptom level. Overall, the results of this study support aspects of Ehlers and Clark’s cognitive model of PTSD; cognitive appraisals of the self and centrality of the event were highly related to levels of distress. However, the current study suggests that overly integrated trauma memories may lead to greater distress and not poorly integrated ones as suggested by Ehlers and Clark.     

COVARIATION WITHIN FUNCTIONAL RESPONSE CLASSES: IMPLICATIONS FOR TREATMENT OF SEVERE PROBLEM BEHAVIOR

Two studies examined the effects of a reductive treatment versus instruction-based treatments on the generalized reduction of problem behaviors. Each study involved a detailed analysis of multiple problem behaviors performed by school-aged youth with severe intellectual disabilities. The analysis examined the contrasting effects of one of two different positive intervention procedures (teaching a positive alternative behavior or providing additional teacher assistance during instruction) versus blocking and/or verbally reprimanding a problem behavior. The focus of each analysis was on the covariation of multiple problem behaviors within functional response classes. Results of the investigation indicated that when only one member of the response class was blocked, a collateral increase was observed in one or more different problem behaviors from the same response class. Alternatively, when 1 participant was taught a functionally equivalent mand response, all problem behaviors in the response class were reduced. Problem behaviors also were reduced for the remaining participant by presenting antecedent teacher assistance. Implications of the research extend to analysis of covariation within response classes and to procedures that result in generalized reduction of problem behaviors within a response class.