On the sampling theory roundations of item response theory models

Item response theory (IT) models are now in common use for the analysis of dichotomous item responses. This paper examines the sampling theory foundations for statistical inference in these models. The discussion includes: some history on the stochastic subject versus the random sampling interpretations of the probability in IRT models; the relationship between three versions of maximum likelihood estimation for IRT models; estimating versus estimating -predictors; IRT models and loglinear models; the identifiability of IRT models; and the role of robustness and Bayesian statistics from the sampling theory perspective.A presidential address can serve many different functions. This one is a report of investigations I started at least ten years ago to understand what IRT was all about. It is a decidedly one-sided view, but I hope it stimulates controversy and further research. I have profited from discussions of this material with many people including: Brian Junker, Charles Lewis, Nicholas Longford, Robert Mislevy, Ivo Molenaar, Donald Rock, Donald Rubin, Lynne Steinberg, Martha Stocking, William Stout, Dorothy Thayer, David Thissen, Wim van der Linden, Howard Wainer, and Marilyn Wingersky. Of course, none of them is responsible for any errors or misstatements in this paper. The research was supported in part by the Cognitive Science Program, Office of Naval Research under Contract No. Nooo14-87-K-0730 and by the Program Statistics Research Project of Educational Testing Service.     

Continuous and discrete latent structure models for item response data

Relations are examined between latent trait and latent class models for item response data. Conditions are given for the two-latent class and two-parameter normal ogive models to agree, and relations between their item parameters are presented. Generalizationss are then made to continuous models with more than one latent trait and discrete models with more than two latent classes, and methods are presented for relating latent class models to factor models for dichotomized variables. Results are illustrated using data from the Law School Admission Test, previously analyzed by several authors.     

Whose Gene Is It? A Case Discussion About Familial Conflict over Genetic Testing for Breast Cancer

A multidisciplinary group of genetic and other professionals discuss a complex case of familial conflict over access to genetic information. One twin wishes to know the results of her deceased mother's tests for BRCA1 mutations; a second twin objects to researchers making this information available. As the case discussion unfolds, the apparent facts of this case are called into question and the lines of ethical certainty become less clear.     

Knowledge of Breast Cancer Genetics Among Breast Cancer Patients and First-Degree Relatives of Affected Individuals

The cloning of BRCA1, a susceptibility gene for inherited breast cancer, has made genetic screening possible for individuals and families whose medical histories are suggestive of an inherited predisposition to breast cancer. To date, few systematic attempts have been made to determine the level of knowledge about breast cancer genetics among women who are likely to seek BRCA1 screening when it becomes widely available. The present study attempted to assess the general knowledge about BRCA1 mutations in two groups: (1) first-degree relatives (FDRs) of breast cancer patients; and (2) women with a previous diagnosis of breast cancer. A self-administered, thirty-item questionnaire was developed through a pilot study. Ten of the items were objective, factual questions about breast cancer genetics. Responses to these questions were used to generate an overall knowledge score for each respondent. The study population was moderately knowledgeable about breast cancer genetics, with an average score of 5.35 out of 10. Counselors should not underestimate the importance of evaluating each counselee's existing knowledge about breast cancer, which can affect the provision and reception of genetic information. In particular, specific areas of knowledge that may be confusing or misunderstood were identified and these topics are discussed in detail.     

The use of the occupational stress indicator (OSI) in factory workers in China

The purpose of the study was to investigate occupational stress among Chinese factory workers (N=342), from three cities of South East China, using the shortened version of the Occupational Stress Indicator (OSI)-2. The results showed that the reliabilities and predictive validity of the OSI-2 subscales and other subscales used for the study were reasonably high. Quite a high percentage of workers perceived high work pressure. The main sources of stress were intrinsic to the job; and the coping strategies that were most frequently used to tackle stress were “control” methods. In addition, “satisfaction on environmental condition” seemed to be a common predictor for job satisfaction, and mental and physical well-being. The logical relationships between job satisfaction, mental well-being and physical well-being in Chinese workers have provided support to the findings obtained in Western countries.     

Exploring the set-theoretical structure of objects by additive trees

Arrangements of feature sets that have been proposed to represent qualitative and quantitative variation among objects are shown to generate identical sets of set-symmetric distances. The set-symmetric distances for these feature arrangements can be represented by path lengths in an additive linear tree. Imperfect versions of these feature arrangements are proposed, which also are indistinguishable by the set-symmetric distance model. The distances for the imperfect versions can be represented by path lengths in an additive imperfectly linear tree. When dissimilarities are defined by the more general contrast model and a constant may be added to proximity data, then for both the perfect and imperfect arrangements an additive tree analysis obtains a perfect fit with an imperfectly linear tree. However, in the case of the contrast model also the distinction between the perfect and imperfect arrangements disappears in that also for the perfect arrangements the resulting tree need no longer be linear.The author is grateful to Mathieu Koppen for detailed comments on an earlier version of this article.     

计算机支持下协同工作的心理学研究

计算机支持下协同工作（ｃｏｍｐｕｔｅｒｓｕｐｐｏｒｔｅｄｃｏｏｐｅｒａｔｉｖｅｗｏｒｋ,简称ＣＳＣＷ）是计算机科学和认知科学的新兴交叉研究领域,主要研究在高技术支持下的群体协作。ＣＳＣＷ中蕴含着大量的心理学研究问题。心理学家需要更好地理解群体协作的性质以评估新技术是否与群体协作相适应,其研究成果会有助于理解如何构建技术和哪些技术可能成功。本文首先从分析ＣＳＣＷ的领域维度入手,然后讨论与之相关的一些重要的心理学研究问题,最后简要介绍国外在该领域进行的研究工作     

The Question of God in an Age of Science: Constructions of Reality and Ultimate Reality in Theology and Science

Both science and theology have lately faced a crisis of authority. Their shared realization of the extent to which knowledge is underdetermined by the data and socially constructed provides a kind of common ground for reconsideration of their respective methods of inquiry as well as of the status of the claims they have warrant to make. Both fields are now consciously and critically employing a models approach. This article proposes criteria for assessing models and applies the criteria to one model from each field. The model of understanding evolution as a struggle for existence is considered from the field of science, and the traditional model for understanding the God-world relation as that of a king's relation to his kingdom is considered from the field of theology. Each of these models is evaluated with respect to its credibility, religious viability, and moral adequacy. In each case an alternative analogy is proposed and argued for.