Distractor selection ratios

A latent variable representation for multiple-choice item and option characteristic curves is presented. Under standard assumptions of conditional independence of item responses and monotonicity of item characteristic curves, a criterion for distractors is proposed based on distractor selection ratios. A connection is made between the proposed criterion and the theory of individual choice behavior, providing new insight. The main results allow for the testing of the criterion from observable data without first specifying a parametric form for the characteristic curves. A series of examples apply the method.     

Synchronization of Logics

Motivated by applications in software engineering, we propose two forms of combination of logics: synchronization on formulae and synchronization on models. We start by reviewing satisfaction systems, consequence systems, one-step derivation systems and theory spaces, as well as their functorial relationships. We define the synchronization on formulae of two consequence systems and provide a categorial characterization of the construction. For illustration we consider the synchronization of linear temporal logic and equational logic. We define the synchronization on models of two satisfaction systems and provide a categorial characterization of the construction. We illustrate the technique in two cases: linear temporal logic versus equational logic; and linear temporal logic versus branching temporal logic. Finally, we lift the synchronization on formulae to the category of logics over consequences systems.     

Exploring the Theory and Paradigm Base for Wraparound

Until recently, family-centered policy and practice used expert models which defined families of children with serious emotional disturbance as dysfunctional A collaborative model, called wraparound, is emerging which engages these families as decision making participants, using naturally occurring strengths to wrap individualized supports around the child and family. However, because wraparound has been defined only through value-based principles, the fidelity of the model is threatened by a developmental paradox. Those who have received training and whose careers have been shaped in more traditional expert models of deficit remediation can interpret these value-based principles as an emergent form of case management methodology. Critical and constructivist paradigms, and ecological systems theory, form a basis for negotiating this paradox to maintain fidelity of wraparound process. Anchored in this base, and derived from wraparound's value-based principles, a single construct with an operative focus is suggested to ensure the integrity of this collaborative model.     

An efficient algorithm for joint correspondence analysis

Joint correspondence analysis is a technique for constructing reduced-dimensional representations of pairwise relationships among categorical variables. The technique was proposed by Greenacre as an alternative to multiple correspondence analysis. Joint correspondence analysis differs from multiple correspondence analysis in that it focuses solely on between-variable relationships. Greenacre described one alternating least-squares algorithm for conducting joint correspondence analysis. Another alternating least-squares algorithm is described in this article. The algorithm is guaranteed to converge, and does so in fewer iterations than does the algorithm proposed by Greenacre. A modification of the algorithm for handling Heywood cases is described. The algorithm is illustrated on two data sets.     

Situation Models: The Mental Leap Into Imagined Worlds

Situation models are mental representations of the state of affairs described in a text rather than of the text itself. Much of the research on situation models in narrative comprehension suggests that comprehenders behave as though they are in the narrated situation rather than outside of it. This article reviews some of this evidence and provides an outlook on future developments.     

Introduction: Neuropsychological Assessment Après Luria

Neuropsychological assessment since Alexander R. Luria's death in 1977 has demonstrated increased sophistication and advancement, and a number of models or approaches to neuropsychological assessment are available worldwide today. This article reviews, in the context of this special issue, Luria's influence on the further development of neuropsychological assessment approaches and methods. Contemporary approaches are summarized and contrasted, and a discussion of neo-Lurian adaptations and extensions of his neuropsychological model is presented. Brief comments about the succeeding articles in this issue help to demonstrate the wide influence sustained by Luria's ideas in various regions of the world.     

Spatial,non-spatial and hybrid models for scaling

In this paper, hierarchical and non-hierarchical tree structures are proposed as models of similarity data. Trees are viewed as intermediate between multidimensional scaling and simple clustering. Procedures are discussed for fitting both types of trees to data. The concept of multiple tree structures shows great promise for analyzing more complex data. Hybrid models in which multiple trees and other discrete structures are combined with continuous dimensions are discussed. Examples of the use of multiple tree structures and hybrid models are given. Extensions to the analysis of individual differences are suggested.1976 Psychometric Society Presidential Address.While people too numerous to list here have contributed ideas, inspiration, and other help, I particularly wish to acknowledge the contributions of Sandra Pruzansky, without whom this paper could not have been written. I would also like to acknowledge the past contributions of my long-time colleague Jih-Jie Chang, without whose help I probably would not have beenasked to write it.     

Canonical/redundancy factoring analysis

The interrelationships between two sets of measurements made on the same subjects can be studied by canonical correlation. Originally developed by Hotelling [1936], the canonical correlation is the maximum correlation betweenlinear functions (canonical factors) of the two sets of variables. An alternative statistic to investigate the interrelationships between two sets of variables is the redundancy measure, developed by Stewart and Love [1968]. Van Den Wollenberg [1977] has developed a method of extracting factors which maximize redundancy, as opposed to canonical correlation.A component method is presented which maximizes user specified convex combinations of canonical correlation and the two nonsymmetric redundancy measures presented by Stewart and Love. Monte Carlo work comparing canonical correlation analysis, redundancy analysis, and various canonical/redundancy factoring analyses on the Van Den Wollenberg data is presented. An empirical example is also provided.Wayne S. DeSarbo is a Member of Technical Staff at Bell Laboratories in the Mathematics and Statistics Research Group at Murray Hill, N.J. I wish to express my appreciation to J. Kettenring, J. Kruskal, C. Mallows, and R. Gnanadesikan for their valuable technical assistance and/or for comments on an earlier draft of this paper. I also wish to thank the editor and reviewers of this paper for their insightful remarks.     

WHAT IS THE ROLE OF SCIENCE IN THE DIALOGUE PROPOSED BY WILLIAM KLINK?

Abstract. Klink rejects the use of ecological models in environmental decision making because their predictions cannot be tested by rigorous scientific methods. I argue that models that cannot be tested according to the rigorous standards of the physical sciences can still be considered “scientific”; they are useful (and, in practice, used) for assessing the impacts of human actions on the environment and choosing between alternative courses of action. It is, however, important to be aware of the uncertainties and to make corrections as new data and insights become available. The interplay between (1) model-based decisions and action and (2) their consequences and subsequent corrections can be regarded as a dialogue between humans and nature (or God) in the sense proposed by Klink. Klink also claims that future actions should be informed by the larger vision of theology and should not be based on science. I suggest that science has an indispensible role. The larger vision is needed to respond to the fundamental religious question: How should I live—and why? But this question cannot be answered without first addressing the fundamental scientific question: How does the world work? I suggest that responses to the first question can be formulated as visions of a future state of existence that we feel compelled to strive to realize, and that science is necessary to provide “maps of reality” needed to realize visions. I also suggest that Christian traditions can probably provide adequate visions; the crucial need is for improving our “maps of reality.”