Maximum likelihood additivity analysis

A maximum likelihood estimation procedure was developed to fit unweighted and weighted additive models to conjoint data obtained by the categorical rating, the pair comparison or the directional ranking method. The scoring algorithm used to fit the models was found to be both reliable and efficient, and the program MAXADD is capable of handling up to 300 parameters to be estimated. Practical uses of the procedure are reported to demonstrate various advantages of the procedure as a statistical method.The research reported here was supported by Grant A6394 to the author from the Natural Sciences and Engineering Research Council of Canada. Portions of this research were presented at the Psychometric Society meeting in Iowa City, Iowa, in May, 1980.Thanks are due to Jim Ramsay, Justine Sergent and anonymous reviewers for their helpful comments.Two MAXADD programs which perform the computations discussed in this paper may be obtained from the author.     

Comparing latent distributions

We consider the problem of comparingm latent population distributions when the observed values are scores on a test battery with binary items. The latent densities are assumed to be normal densities, and we consider a test for equality of the means as well as a test equality of the variances. In addition, we consider a longitudinal model, where the test battery has been applied to the same individuals at different points in time. This model allows for correlations between the latent variable at different time points, and methods are discussed for estimating the correlation coefficient.This work was supported in part by a grant from the Danish Social Science Research Council.     

Statistical inference for false positive and false negative error rates in mastery testing

This paper describes an asymptotic inferential procedure for the estimates of the false positive and false negative error rates. Formulas and tables are described for the computations of the standard errors. A simulation study indicates that the asymptotic standard errors may be used even with samples of 25 cases as long as the Kuder-Richardson Formula 21 reliability is reasonably large. Otherwise, a large sample would be required.This work was performed pursuant to Grant No NIE-G-78-0087 with the National Institute of Education, Department of Health, Education and Welfare, Huynh Huynh, Principal Investigator. Points of view or opinions stated do not necessarily reflect NIE position or policy and no official endorsement should be inferred. The editorial assistance of Joseph C. Saunders is gratefully acknowledged.     

Working on Gender as a Gender-Nonconformist

No abstract available for this article.     

Imitation and novelty in product development

A human stigmergy model of product development through a series of incremental novelties and imitations is obtained by observing the isomorphism between solution trees generated by groups of humans participating in online games like Foldit, self-organizing topics in online learning systems, product evolution through a combination of innovation and imitation in the cell phone industry, and social networks formed over the past 40 years in creation of the Boston biotech commons. The model incorporates two very simple rules: (1) preferential attachment, and (2) the combination of existing product designs into a single design. A computer model used to simulate the model produces product evolution networks isomorphic to observed solution trees and product evolution trees. Additionally, industries with a high degree of novelty produce a product evolution network with scale-free and betweenness centrality structure.     

From workplace attachment to commuter satisfaction before and after a workplace relocation

While attention has been paid to travel satisfaction studies during the last decade, less research has investigated the relationship between the influence of a sense of place – and more particularly the psycho-environmental concepts of workplace attachment and workplace satisfaction – and commuting satisfaction. Using a retrospective survey, this paper focuses on the relocation of a workplace within the city of Montréal (Canada); the McGill University Healthcare Centre. It examines the motivations and barriers involved in the evolution of commuting characteristics, using the theoretical framework of mobility biographies. The empirical analysis includes a large dataset of independent variables, applying a multinomial logistic model in order to explain the transition of the employees’ commuting satisfaction. With regard to the measurement of change in commuting satisfaction, the findings confirm the role of attitudes, while taking into account the contextual differences before and after relocation. The change in travel time is found to be an important factor in the evolution of commuter satisfaction, whereby reduced commuting time improves satisfaction, as expected. In addition, the more an employee is attached to the new workplace, the more the commuting satisfaction will increase. The results provide further evidence that the meaning of the workplace goes beyond a location or a space, and opens up new avenues for research in travel behavior.     

Different Effects of Cognitive Shifting and Intelligence on Creativity

The relationship between creativity and executive control has long been controversial. Some researchers view creative thinking as a defocused process with little executive control involvement, whereas others claim that executive control plays a vital role in creative thinking. In this study, we focused on one subcomponent of executive control, cognitive shifting, and examined its relationship with creativity by using latent variable analysis and structural equation modeling. We also analyzed whether this relation was mediated by intelligence. The results showed that: (a) cognitive shifting ability had a positive relationship with creativity, but only on the quantitative aspects (fluency and flexibility); (b) Intelligence had a positive relationship with both quantitative and qualitative aspects (originality) of creativity, and its effect on qualitative aspect was stronger than that on the quantitative aspect; (c) There was a mediating effect of intelligence on the relationship between creativity cognitive and shifting.     

Transitions in sleep problems from late adolescence to young adulthood: A longitudinal analysis of the effects of peer victimization

Adolescence is a developmental period with high vulnerability to sleep problems. However, research identifying distinct patterns and underlying determinants of sleep problems is scarce. This study investigated discrete subgroups of, changes in, and stability of sleep problems. We also examined whether peer victimization influenced sleep problem subgroups and transitions in patterns of sleep problems from late adolescence to young adulthood. Sex differences in the effects of peer victimization were also explored. In total, 1,455 male and 1,399 female adolescents from northern Taiwan participated in this longitudinal study. Latent transition analysis was used to examine changes in patterns of sleep problems and the effects of peer victimization on these changes. We identified three subgroups of sleep problems in males and two in females, and found that there was a certain level of instability in patterns of sleep problems during the study period. For both sexes, those with greater increases in peer victimization over time were more likely to change from being a good sleeper to a poor sleeper. The effects of peer victimization on baseline status of sleep problems, however, was only significant for males, with those exposed to higher levels of peer victimization more likely to be poor sleepers at baseline. Our findings reveal an important role of peer victimization in predicting transitions in patterns of sleep problems. Intervention programs aimed at decreasing peer victimization may help reduce the development and escalation of sleep problems among adolescents, especially in males.