Improved estimators of regression coefficients in measurement error models

This paper is concerned with methods of reducing variability and computer time in a simulation study. The Monte Carlo swindle, through mathematical manipulations, has been shown to yield more precise estimates than the “naive” approach. In this study computer time is considered in conjunction with the variance estimates. It is shown that by this measure the naive method is often a viable alternative to the swindle. This study concentrates on the problem of estimating the variance of an estimator of location. The advantage of one technique over another depends upon the location estimator, the sample size, and the underlying distribution. For a fixed number of samples, while the naive method gives a less precise estimate than the swindle, it requires fewer computations. In addition, for certain location estimators and distributions, the naive method is able to take advantage of certain shortcuts in the generation of each sample. The small amount of time required by this “enlightened” naive method often more than compensates for its relative lack of precision.     

The small sample properties of the reset test as applied to systems of equations

The RESET test for functional misspecification is generalised to cover systems of equations, and the properties of 7 versions are studied using Monte Carlo methods. The Rao F -test clearly exhibits the best performance as regards correct size, whilst the commonly used LRT (uncorrected for degrees-of-freedom), and LM and Wald tests (both corrected and uncorrected) behave badly even in single equations. The Rao test exhibits correct size even in ten equation systems, which is better than previous research concerning autocorrelation tests. The power of the test is low, however, when the number of equations grows and the correlation between the omitted variables and the RESET proxies is small.     

近代的机械论与辩证论:一般系统论思想形成的逻辑环节

近代科学哲学思想对一般系统论的创立产生了重大影响。近代科学哲学思想可以分为两个时期:第一个时期是15世纪下半叶到18世纪末的形而上学整体观时期,这一时期完成了对自然界各门类深层规律的揭示,为人类的认识达到新的整体化阶段创造了条件;第二个时期是19世纪的辩证整体观时期,这一时期则揭示出世界就是普遍联系的辩证整体。这两个时期都是一般系统论思想得以形成的逻辑环节。     

Did send-down experience benefit youth? A reevaluation of the social consequences of forced urban–rural migration during China’s Cultural Revolution

During China’s Cultural Revolution, a large proportion of urban youth were forced to go to the countryside as a result of the state’s “send-down” policy. Past research has been ambivalent about the long-term social consequences for the Chinese youth who experienced send-down. Some scholars have suggested that the send-down experience may have yielded beneficial effects. To test this claim, we analyze data from the Survey of Family Life in Urban China, which we conducted in three large cities in 1999. Questions available in this data set allow us to ascertain the send-down experience of both the respondent and a sibling and educational attainment at the times of send-down and return. Our analyses of the new data show that the send-down experience does not seem to have benefited the affected Chinese youth. Differences in social outcomes between those who experienced send-down and those who did not are either non-existent or spurious due to other social processes.     

Individual strategies for coping with stress at work: A review

This paper discusses some of the conceptual and methodological issues involved in the study of coping. It focuses on individual coping with work and work-related problems, and adopts a transactional framework for the definition of the key concepts of stress, appraisal and coping. It identifies and reviews 17 recent papers which are representative of the coping literature, as defined by the scope of the paper. What it draws out of this review largely concerns issues of measurement, and four particular issues are flagged as important for future research. It concludes that there is a need for more and more adequate studies, particularly in relation to the classification and modelling of coping, and that the adequacy of those future studies should be partly judged in terms of how well they deal with the issues raised here.     

PERCEIVED INFORMATION STRUCTURE: IMPLICATIONS FOR DECISION SUPPORT SYSTEM DESIGN

Top-level decision making in business organizations is characterized by high degrees of uncertainty, incomplete information, and conflicting objectives. To support top-level decision making effectively, decision support systems (DSSs) have been proposed. Information supplied by a DSS must be selective in that not all possible information sets may be feasibly or economically represented in the data base. This study suggests that discovery of perceptual complexity (dimensionality) of information items, and the subsequent categorization of decision makers having the same perceptions of those information items, is a first step in the ultimate design of an effective DSS. Through the use of multidimensional scaling in a field setting, this study shows the feasibility of creating relatively homogeneous groups of decision makers according to the content and number of dimensions associated with various information items. Further results of the research suggest that information can be tailored to classes of users, which has cost-benefit implications as well as the potential to improve the quality of the resultant decisions.     

Conceptualizing Effects of Office Information Systems: A Methodology and Application for the Study of Alpha,Beta, and Gamma Changes*

This article applies the concepts of alpha, beta, and gamma changes to test whether the implementation of a new office information system with networking capabilities changes the way organizational members conceptualize office work. The traditional approach (t-test) was used to measure alpha change and indicated little change in how effectively the respondents felt they performed eight generic office activities before implementation (T1) and nine months after implementation (T2). However, considerable change was detected between effectiveness reported at T1 and a retrospective assessment of T1 effectiveness reported at T2 (called “then” assessments). Strong change was also detected between “then” assessments and T2 effectiveness reported at T2, indicating beta change. Multiple hierarchical tests showed that most of the change was actually gamma change; the T2 and the “then” factor structures and covariances differed significantly. This study supports propositions that using computers to accomplish organizational work may be associated with different conceptualizations of work, which may create ambiguity and uncertainty if training and management policies do not respond appropriately. Finally, this study provides an expanded version of a prior solution to detecting alpha, beta, and gamma changes.     

Increasing the Effectiveness of Student Evaluation of Instructor Data through a Factor Score Comparative Report

Effective student evaluation of instructor instruments must provide norm, or comparative, data to aid interpretation. This note highlights an innovative factor score comparative report. Rather than merely reporting comparative data on individual questions items, the innovative report provides comparative percentile data on the six factors underlying our thirty-three item questionnaire. The faculty indicated overwhelming support for the new report. The note also briefly mentions three other activities that are essential for student evaluation of instructor data to improve teacher effectiveness. Our goal is to stimulate other colleges to adopt the innovative norming practice once they have validated their local evaluation instruments. College-wide improvement of teaching will occur through such do-it-yourself efforts and only decision science faculty are technically qualified to lead such efforts.     

Education TEAM-SIZE EFFECTS ON BUSINESS GAME PERFORMANCE AND DECISION-MAKING BEHAVIORS

The effects of various decision-making team sizes in a complex business game were studied. Firm size was associated with nonlinear performance results and decision curves resulting in differential learning outcomes, learning sources, attrition rates, and decisionmaking behaviors. A three-member format produced the highest learning levels while two-member firms experienced only marginally significant knowledge increases. Single-member firms experienced the most bankruptcies and dropouts. A contingency view of gaming effectiveness is suggested.     

Evaluating and Refining Expert Critiquing Systems: A Methodology*

Expert critiquing systems are a rapidly growing class of intelligent decision support systems that apply artificial intelligence techniques to criticize a user's proposed solution to a problem. Critic programs now exist in the medical, engineering, programming, knowledge acquisition, word processing, and other domains. Critic refinement is a nontrivial activity that, even when done well, consumes a sizable fraction of the complete effort to build and deploy a critiquing system. To ease that effort, it is important to adopt a rigorous approach that allows one to reproducibly measure the degree of success of the current critic version and to predict which refinements will improve the critic further. The current article presents one such approach with actual case studies that illustrate its usage and elaborate selected aspects of the refinement process.