建立有效的证券投资组合

在我国股市，投资组合是否真能有效降低风险？如何建立证券投资组合？组合的规模以多少为宜？这些基本问题的研究，对提高组合管理的效率具有重要的参考价值和指导作用．本文从分析的角度对这些问题进行了研究，同时指出在成熟的证券市场中投资组合理论广阔的应用前景．     

21世纪住宅设计发展趋势

随着科学技术进步和人们生活水平的提高,人们已经从长期被动地适应福利分配住房到主动地选择住房,人们对住宅选择的余地越来越大,对住宅功能与品质的要求越来越高.住宅市场化条件下,如何适应这种变化,满足人们不同的居住需求?什么样的住宅才是理想的住宅?未来住宅设计究竟要解决哪些问题?经过几年的市场洗炼,我国的住宅设计已逐步从理念和概念的炒作,走向理性和务实的层面上.未来住宅的设计向何处去,成为很多规划师、建筑师和开发商深为关注并努力探讨的课题.     

Bias Reduction in Quasi-Experiments With Little Selection Theory but Many Covariates

Abstract: In observational studies, selection bias will be completely removed only if the selection mechanism is ignorable, namely, all confounders of treatment selection and potential outcomes are reliably measured. Ideally, well-grounded substantive theories about the selection process and outcome-generating model are used to generate the sample of covariates. However, covariate selection is more heuristic in actual practice. Using two empirical data sets in a simulation study, we investigate four research questions about bias reduction when the selection mechanism is not known but many covariates are measured: (1) How important is the conceptual heterogeneity of the covariate domains in the data set? (2) How important is the number of covariates assessing each domain? (3) What are the joint effects of this conceptual heterogeneity and of the number of covariates per domain? (4) What happens to bias reduction when the set of covariates is deliberately impoverished by removing the covariates most responsible for selection bias, thus ensuring a slightly smaller but still heterogeneous set of covariates? The results indicate: (1) increasingly more bias is reduced as the number of covariate domains and the number of covariates per domain increase, though the rate of bias reduction is diminishing in each case; (2) sampling covariates from multiple heterogeneous covariate domains is more important than choosing many measures from fewer domains; (3) the most heterogeneous set of covariate domains removes almost all of the selection bias when at least five covariates are assessed in each domain; and (4) omitting the most crucial covariates generally replicates the pattern of results due to the number of domains and the number of covariates per domain, but the amount of bias reduction is less than when all variables are included and will surely not satisfy all consumers of causal research.     

How to be a good teache

What makes a good teacher?How should teachers talk to students?How should teachers give instructions?Who should talk in class?What are the best kinds of lesson?How important is it to follow a pre-arranged plan?     

Learning outcomes: What are they? Who defines them? When and where are they defined?

This study aims to illuminate the phenomenon of learning outcomes. Although a wide range of studies in education have examined the phenomenon in various ways, few have investigated how scholars themselves conceive of it. To provide insight into this issue, the paper explores the following questions: How is the term “learning outcome” defined? By whom? When? Where? The investigation is based on a document analysis of a selection of 33 scholarly written documents in which the concept is discussed. Findings indicate that there is a dominant established definition of the term learning outcome. However, a wide range of alternative definitions are also identified. These assert that learning outcomes involve more than what can be described in pre-specified and measurable terms.     

Development, Implementation, and Validation of a Computerized Test for Statewide Assessment

How does a testing component function in an integrated learning system? How can you customize computerized tests to meet local specifications? How are computerized tests implemented and evaluated? Is the pay-off of computerized testing justified?     

Learning natural selection through computational thinking: Unplugged design of algorithmic explanations

Computational thinking (CT) is a way of making sense of the natural world and problem solving with computer science concepts and skills. Although CT and science integrations have been called for in the literature, empirical investigations of such integrations are lacking. Prior work in natural selection education indicates students struggle to explain natural selection in different contexts and natural selection misconceptions are common. In this mixed methods study, secondary honors biology students learn natural selection through CT by engaging in the design of unplugged algorithmic explanations. Students learned CT principles and practices and applied them to learn and explain the natural selection process. Algorithmic explanations were used to scaffold transfer of natural selection knowledge across contexts through investigation of three organisms and the creation of generalized natural selection algorithms. Students' pre- and post-unit algorithmic explanations of natural selection were analyzed to answer the following research questions: (a) How do students' conceptions of natural selection change over the course of a CT focused unit? (b) What is the relationship between CT and natural selection in students' algorithmic explanations? (c) What are students' perspectives of learning natural selection with CT? Results indicate students' conceptions of natural selection increased and natural selection misconceptions decreased over the course of the unit. Within their post-unit algorithmic explanations, students used specific CT principles in conjunction with natural selection concepts to explain natural selection, which helped them to learn the details of the natural selection process and correct their natural selection misconceptions. Students indicated the use of CT in unplugged algorithmic explanations in different contexts helped them learn natural selection. This study shows unplugged CT can be used to teach students science content, and it provides an example for further CT and science integrations. Implications for the field are discussed.     

当实验室主任的体会

实验室主任的职责是什么?应如何开展工作?实验室如何可持续发展?实验教学改革走向何方?实验室如何在学生能力培养方面发挥作用?作者结合十余年的工作经历谈了当实验室主任的体会。     

Teaching About Communicating Assessment Results and Grading

How should a course on classroom assessment differ from an introductory psychometrics course? How should such a course be taught? How large a role should instruction concerning grading and communicating play in such a course?     

The Conceptual Framework for the Development of a Mathematics Performance Assessment Instrument

How can you align instruction, learning, and assessment in an educationally sound way? How can you define and measure competence in mathematics? What areas of competence do you need to specify and how? How can one evaluate the validity and consequences of using a particular assessment instrument or technique?     

Portfolios, Accountability, and an Interpretive Approach to Validity

How can the results of classroom-based portfolio assessment be communicated outside the classroom? How might a portfolio-based assessment system be designed and implemented? How can we evaluate the merits of portfolio-based assessments?     

Are U.S. Students the Most Heavily Tested on Earth?

How should amount of testing be defined? On average, how many hours does a U.S. student spend on testing? How does this compare with testing time in other countries? How do the type and purpose of testing vary from U.S. to other countries?     

Ethical Codes in the Professions

Why do professions develop ethical codes? How similar are ethical codes across professions? How are codes enforced? Should the measurement profession develop such a code?     

苏霍姆林斯基的爱情教育观及对性教育的启示

什么是爱情?怎样对待爱情?在青年刚懂得爱情的时候就要教育他们怎样去爱,怎样陶冶爱情这个心灵的高尚情感。苏霍姆林斯基视爱情为德育教育的重要内容,并从教育学的角度对此进行了深刻的分析研究,对我国的性教育有着重要的借鉴意义。     

Inclusive education: Open debates and the road ahead

This special issue is devoted to the outcomes of the 48th International Conference of Education, “Inclusive Education: The Way of the Future” (Geneva, 25–28 November 2008). In addition to presenting the conclusions and recommendations from the conference, this introduction tackles a wide range of questions in the field of inclusive education on which there are still controversy and debate. The issue draws together a selection of articles that analyze these open debates at a deeper level. Special emphasis is placed on several issues: Should inclusive education be a comprehensive approach or follow a policy of piecemeal social engineering? How can educational systems pursue equity and quality simultaneously? What is the role of government, and of decentralization and autonomy? What teaching methods are needed, and what changes in teacher education, development and motivation? Finally, what are the roles of communities, social attitudes, and behaviours?     

Portfolio Assessment: A Theoretical Esthnate of Score Reliability

What components should be included in a portfolio of student work? How can the contents of portfolios be scored? How is reliability affected as the number of entries in the portfolio increases? What will it cost to obtain reliable scores?     

The Publication Process in Educational Measurement

Why is it important to publish your research? How are papers reviewed before publication decisions are made? How can you select the right journal for your paper? How do EM:” and other measurement journals compare in content, orientation, and other characteristics?     

Educational and Employment Testing: Changing Concepts in Measurement and Policy

How will the expansion of the concept of construct validity affect validation practice in employment testing? How does the need for consequential validity differ in educational and employment testing? How do the research bases differ for performance assessment in these settings? Are there parallel trends in policies for test use in education and industry?     

Understanding of graphs in social science undergraduate students: selection and interpretation of graphs

How do university students understand the graphs that they read in their textbooks? How does their knowledge regarding the content and their statistical training influence this understanding? Does the kind of task demand also influence this understanding? To answer these questions, we asked a group of psychology students and a group of economics students to choose the most suitable graph for presenting the results of different psychological research studies (reports) (selection task) or to explain in words the results of the same reports shown by means of their graphic representations only (interpretation task). The results showed there were very few differences between groups. Most of the students were able to relate textual information to the adequate graph, but also revealed significant shortcomings and mistakes in their understanding of important syntactic aspects of graphs. They also interpreted the graphs correctly but their interpretation had different levels of complexity, which were not always optimal. We also identified significant differences regarding the difficulty of the reports and the kinds of misinterpretations of graphs. The two tasks thus revealed different pictures of students’ skills in reading and interpreting graphs and, consequently, how the characteristics of task demands influence their performance.     

Development and Validation of Professional Development Resource Materials for Teachers Cbvering Commwnicathg and Interpreting Assessment Results

How were the materials tested? How did the reactions of teachers compare to those of measurement students? How can these materials be used effectively?