Creating Misspecified Models in Moment Structure Analysis

Psychometrika - To understand how SEM methods perform in practice where models always have misfit, simulation studies often involve incorrect models. To create a wrong model, traditionally one...     

Assessing The Discriminant Validity Of Regression Models And Subjectively Weighted Models Of Judgments

When either regression models or subjectively weighted models are used as aids in making placement decisions, the discriminant validity of these models is of interest. When all predictor information is used in all decisions, models which assign equal weights cannot simultaneously show high levels of predictive accuracy and discriminant validity; in some settings, both regression models and subjectively weighted models may. The discriminant validity of regression models and of subjectively weighted models was investigated in two judgment experiments. Both types of models showed high levels of accuracy and cross-validity in both experiments. Regression models showed discriminant validity in both experiments, while subjectively weighted models failed to show discriminant validity in the second. The homogeneity of cue validities appeared to moderate both the level of discriminant validity and the relationship between similarity of subjective models, across tasks, and discriminant validity.     

Understanding Linkages Among Mixture Models

The methodological literature on mixture modeling has rapidly expanded in the past 15 years, and mixture models are increasingly applied in practice. Nonetheless, this literature has historically been diffuse, with different notations, motivations, and parameterizations making mixture models appear disconnected. This pedagogical review facilitates an integrative understanding of mixture models. First, 5 prototypic mixture models are presented in a unified format with incremental complexity while highlighting their mutual reliance on familiar probability laws, common assumptions, and shared aspects of interpretation. Second, 2 recent extensions—hybrid mixtures and parallel-process mixtures—are discussed. Both relax a key assumption of classic mixture models but do so in different ways. Similarities in construction and interpretation among hybrid mixtures and among parallel-process mixtures are emphasized. Third, the combination of both extensions is motivated and illustrated by means of an example on oppositional defiant and depressive symptoms. By clarifying how existing mixture models relate and can be combined, this article bridges past and current developments and provides a foundation for understanding new developments.     

A Person Fit Test For Irt Models For Polytomous Items

A person fit test based on the Lagrange multiplier test is presented for three item response theory models for polytomous items: the generalized partial credit model, the sequential model, and the graded response model. The test can also be used in the framework of multidimensional ability parameters. It is shown that the Lagrange multiplier statistic can take both the effects of estimation of the item parameters and the estimation of the person parameters into account. The Lagrange multiplier statistic has an asymptotic χ²-distribution. The Type I error rate and power are investigated using simulation studies. Results show that test statistics that ignore the effects of estimation of the persons’ ability parameters have decreased Type I error rates and power. Incorporating a correction to account for the effects of the estimation of the persons’ ability parameters results in acceptable Type I error rates and power characteristics; incorporating a correction for the estimation of the item parameters has very little additional effect. It is investigated to what extent the three models give comparable results, both in the simulation studies and in an example using data from the NEO Personality Inventory-Revised.     

A Counterexample To Miller And Farr's Algorithm For The Index Of Redundancy

Miller and Farr's algorithm for the index of redundancy is shown to be incorrect by means of a counterexample. It is also argued that their interpretation of the proportion of the total variance in one multivariate response explained by another multivariate response with respect to a given component of the first response is misleading.     

Perceptions Of Benefits and Losses Associated With The Use and Discontinuance Of Anabolic-Androgenic Steroids Among Male Bodybuilders

Abstract

Research has shown the mesomorphic physique to be the most preferred body type among males. Specifically, the hypermesomorphic physique, which displays extreme muscularity and definition, is the most desired (Tucker, 1983). Mishkind, Rodin, Silberstein, and Streigel-Moore (1987) concluded that multiple reasons exist for this preference, most notably the intimate ties that exist among societal conceptions of masculinity, the male sex role, and the mesomorphic physique. Bodybuilding has been perceived as an avenue by which males attempt to develop the preferred mesomorphic physique, and, at times, anabolic-androgenic steroids (AAS) have been ingested as a means for further development. This study entailed in-depth interviews with 10 male bodybuilders, all of whom had taken, or were currently taking, AAS. This article presents the findings of the interviews concerning the perceived benefits of and psychological dependency on AAS. The data, particularly responses concerning psychological dependency, are noted within Mishkind et al.'s framework as a mechanism to avoid loss of muscle strength, muscle mass, and masculinity.     

Structures And Structuralism In Contemporary Philosophy Of Mathematics

In recent philosophy of mathematics avariety of writers have presented ``structuralist'views and arguments. There are, however, a number ofsubstantive differences in what their proponents take``structuralism' to be. In this paper we make explicitthese differences, as well as some underlyingsimilarities and common roots. We thus identifysystematically and in detail, several main variants ofstructuralism, including some not often recognized assuch. As a result the relations between thesevariants, and between the respective problems theyface, become manifest. Throughout our focus is onsemantic and metaphysical issues, including what is orcould be meant by ``structure' in this connection.     

Music In The Moment

Book Information Music In The Moment. By Jerrold Levinson. Cornell University Press. Ithaca. 1997. Pp. 175. Hardback.     

A Unifying Principle Of Biological And Cultural Evolution And Its Implications For The Future

In this article I analyze a regular pattern in the developmental and evolutionary processes, formed by a gradual shortening of developmental stages. This shortening is the expected result of a selection process, in the biological as well as in the cultural evolutionary process. Biology and culture are in this way unified by a common mechanism. A mathematical analysis further indicates a vital condition for a continued progress of human culture, especially for a continued progressive scientific evolution, implying continued shortening of mental developmental stages by means of enhanced education.     

An Analysis Of Quine's ``Ontological Reduction And The World Of Numbers'

A detailed analysis of Quine's paper on ontologicalreduction shows that the proxy-function requirement, in hischaracterization of the concept of ontological reduction,is superfluous for blocking Pythagoreism and inappropriate for a generalblockade of ontological monism.     

The Specific Analysis of Structural Equation Models

Conventional structural equation modeling fits a covariance structure implied by the equations of the model. This treatment of the model often gives misleading results because overall goodness of fit tests do not focus on the specific constraints implied by the model. An alternative treatment arising from Pearl's directed acyclic graph theory checks identifiability and lists and tests the implied constraints. This approach is complete for Markov models, but has remained incomplete for models with correlated disturbances. Some new algebraic results overcome the limitations of DAG theory and give a specific form of structural equation analysis that checks identifiability, tests the implied constraints, equation by equation, and gives consistent estimators of the parameters in closed form from the equations. At present the method is limited to recursive models subject to exclusion conditions. With further work, specific structural equation modeling may yield a complete alternative to the present, rather unsatisfactory, global covariance structure analysis.     

The Rational Analysis Of Mind And Behavior

Rational analysis (Anderson 1990, 1991a) is an empiricalprogram of attempting to explain why the cognitive system isadaptive, with respect to its goals and the structure of itsenvironment. We argue that rational analysis has two importantimplications for philosophical debate concerning rationality. First,rational analysis provides a model for the relationship betweenformal principles of rationality (such as probability or decisiontheory) and everyday rationality, in the sense of successfulthought and action in daily life. Second, applying the program ofrational analysis to research on human reasoning leads to a radicalreinterpretation of empirical results which are typically viewed asdemonstrating human irrationality.