Checking the Assumptions of Rasch's Model for Speed Tests

Two new tests for a model for the response times on pure speed tests by Rasch (1960) are proposed. The model is based on the assumption that the test response times are approximately gamma distributed, with known index parameters and unknown rate parameters. The rate parameters are decomposed in a subject ability parameter and a test difficulty parameter. By treating the ability as a gamma distributed random variable, maximum marginal likelihood (MML) estimators for the test difficulty parameters and the parameters of the ability distribution are easily derived. Also the model tests proposed here pertain to the framework of MML. Two tests or modification indices are proposed. The first one is focused on the assumption of local stochastic independence, the second one on the assumption of the test characteristic functions. The tests are based on Lagrange multiplier statistics, and can therefore be computed using the parameter estimates under the null model. Therefore, model violations for all items and pairs of items can be assessed as a by-product of one single estimation run. Power studies and applications to real data are included as numerical examples.     

What's measured is not necessarily managed: cognitive contingencies of organizational measurement

Organizational measurement is necessary for managing incremental improvements or change efforts. Some have argued that indicators of financial performance measure the past and should be joined by "lead" measures such as management development and customer relations, assumed to be drivers of performance. Approaches of "lead" measures have met criticism for not contributing to operational management. The present is an empirical case study where measures from a customer satisfaction survey and a management assessment instrument were analyzed and compared to actual measures of financial performance. The effects of measures obtained seem to depend on the interpretations and reflection taking place in the organization. The pursuit of "lead" indicators did not seem to drive results. Counter-intuitively, higher scores on these measures were related to poorer financial performance. The explication of and reflection on the underlying dynamic seemed to turn the development in a profitable direction.     

The growing complexity of international policy in intellectual property

Intellectual property has historically been a self-contained policy at the international level. With the introduction of the TRIPs Agreement in 1994 and developments since the conclusion of the TRIPs Agreement, the relationship between intellectual property policy and other areas of public policy has become much more complex and interactive. This shift reflects the centrality of intellectual property in the knowledge economy, the rapid development of enabling technologies, notably the Internet and biotechnology, and the advent of the networked society. The consequences of this shift are manifold and herald the increased sophistication and complexity that may be expected of intellectual property regimes in the knowledge economy. An earlier version of this paper was presented at an international conference, “The Ethics of Intellectual Property Rights and Patents,” held in Warsaw, Poland on 23–24 April, 2004.     

Partial Knowledge of Word Meanings: Thematic and Taxonomic Representations

The type of information (taxonomic or thematic) available at different levels of knowledge was investigated. Following extensive norming to identify taxonomic and thematic associates of low-frequency nouns, participants determined if taxonomic or thematic associates were meaningfully related to target words at three levels of knowledge: target words they correctly defined (known), recognized as familiar (frontier), or mistakenly denied as part of the language (unknown). In another experiment, participants reported which type of relationship (taxonomic or thematic) was preferred. Results indicated that both types of information were available at all levels of knowledge. However, accuracy and preference were greater for taxonomic associates across word levels. A differential increase in available thematic information relative to taxonomic information was found. Implications for the acquisition and representation of word meanings are discussed.     

Strategy choices in simple and complex addition: Contributions of working memory and counting knowledge for children with mathematical disability

Groups of first-grade (mean age = 82 months), third-grade (mean age = 107 months), and fifth-grade (mean age = 131 months) children with a learning disability in mathematics (MD, n = 58) and their normally achieving peers (n = 91) were administered tasks that assessed their knowledge of counting principles, working memory, and the strategies used to solve simple (4+3) and complex (16+8) addition problems. In all grades, the children with MD showed a working memory deficit, and in first grade, the children with MD used less sophisticated strategies and committed more errors while solving simple and complex addition problems. The group differences in strategy usage and accuracy were related, in part, to the group difference in working memory and to group and individual differences in counting knowledge. Across grade-level and group, the switch from simple to complex addition problems resulted in a shift in the mix of problem-solving strategies. Individual differences in the strategy mix and in the strategy shift were related, in part, to individual differences in working memory capacity and counting knowledge.     

Interactions between Knowledge,Action and Commitment within Agent Dynamic Logic

This paper considers a new class of agent dynamic logics which provide a formal means of specifying and reasoning about the agents activities and informational, motivational and practical aspects of the behaviour of the agents. We present a Hilbert-style deductive system for a basic agent dynamic logic and consider a number of extensions of this logic with axiom schemata formalising interactions between knowledge and commitment (expressing an agent s awareness of her commitments), and interactions between knowledge and actions (expressing no learning and persistence of knowledge after actions). The deductive systems are proved sound and complete with respect to a Kripke-style semantics. Each of the considered logics is shown to have the small model property and therefore decidable.Presented by Ewa Orlowska     

Local influence analysis of nonlinear structural equation models

By regarding the latent random vectors as hypothetical missing data and based on the conditional expectation of the complete-data log-likelihood function in the EM algorithm, we investigate assessment of local influence of various perturbation schemes in a nonlinear structural equation model. The basic building blocks of local influence analysis are computed via observations of the latent variables generated by the Metropolis-Hastings algorithm, while the diagnostic measures are obtained via the conformal normal curvature. Seven perturbation schemes, including some perturbation schemes on latent vectors, are investigated. The proposed procedure is illustrated by a simulation study and a real example. Acknowledgment: This research is fully supported by a grant (CUHK 4243/02H) from the Research Grant Council of the Hong Kong Special Administration Region. The authors are indebted to ICPSR and the relevant funding agency for allowing use of their data, and to the Editor and reviewers for their valuable comments for improving the paper.     

Pragmatic versus form-based accounts of referential contrast: evidence for effects of informativity expectations

Characterizing the relationship between form-based linguistic knowledge and representation of context has long been of importance in the study of on-line language processing. Recent experimental research has shown evidence of very rapid effects of referential context in resolving local indeterminacies on-line. However, there has been no consensus regarding the nature of these context effects. The current paper summarizes recent work covering a range of phenomena for which referential contrast has been shown to influence on-line processing, including prenominal and postnominal modification, focus operators, and intonational focus. The results of the body of work suggest that referential context effects are not limited to situations in which the linguistic form of the utterance directly specifies the point of contact with context. Rather, context effects of a pragmatic, Gricean nature appear to be possible, suggesting the relationship between linguistic form and context in rapid on-line processing can be of a very indirect nature.