Using Wherry's Adjusted R 2 and Mallow's Cp for Model Selection From All Possible Regressions

Selecting a subset of predictors from a pool of potential predictors continues to be a common problem encountered by applied researchers in education. Because of several limitations associated with stepwise variable selection procedures, the examination of all possible regression solutions has been recommended. The authors evaluated the use of Mallow's C_p and Wherry's adjusted R ² statistics to select a final model from a pool of model solutions. Neither the C_p nor the adjusted R ² statistic correctly identified the underlying regression model any better and was generally worse than the stepwise selection method, which itself was poor. Using any of the model selection procedures studied here resulted in biased estimates of the authentic regression coefficients and underestimation of their standard errors. The use of theory and professional judgment is recommended for the selection of variables in a prediction equation.     

Further Reflections on Hypothesis Testing and Editorial Policy for Primary Research Journals

Questions have recently been raised about the value of statistical hypothesis testing, as well as the associated policy implications for publishing empirically based research in professional journals. In this Reflections note, we extend our (Robinson and Levin, 1997) earlier thoughts on what could, should, and should not be done to existing editorial practices.     

Constructive Criticisms of Methodological and Editorial Practices

Thompson (1999a and elsewhere) has taken strong positions on a variety of methodological issues. In this article, the authors critique some of those positions and provide alternative views for each.     

编辑决策研究断想

编辑决策贯穿于编辑活动始终,是编辑学的关键范畴,具有重要的研究意义;具体而言包括三个方面:出版产业化环境下编辑决策的一般过程与普遍原理、编辑决策的特殊规律及其实际应用、编辑活动史上编辑决策的现实启示;必须创新研究方法,凝练出具有普遍指导意义的编辑决策理论.     

Problems With Null Hypothesis Significance Testing (NHST): What Do the Textbooks Say?

The first of 3 objectives in this study was to address the major problem with Null Hypothesis Significance Testing (NHST) and 2 common misconceptions related to NHST that cause confusion for students and researchers. The misconceptions are (a) a smaller p indicates a stronger relationship and (b) statistical significance indicates practical importance. The second objective was to determine how this problem and the misconceptions were treated in 12 recent textbooks used in education research methods and statistics classes. The third objective was to examine how the textbooks' presentations relate to current best practices and how much help they provide for students. The results show that almost all of the textbooks fail to acknowledge that there is controversy surrounding NHST. Most of the textbooks dealt, at least minimally, with the alleged misconceptions of interest, but they provided relatively little help for students.     

对我国学术研究的若干思考

学术研究有理论研究和应用研究之分,但研究对象都来源于现实世界,具有经世致用的品格,在实践中具有理论意义和应用价值。文章通过对中国几大论文数据库检索的查证,发现我国学术研究的过程中存在一些值得注意的现象,同时对学术研究的目的和意义、研究中存在的问题、学术研究方法等提出了’一家之言。     

Statistical Significance and Effect Size in Education Research: Two Sides of a Coin

Abstract

In education research, statistical significance and effect size are 2 sides of 1 coin; they complement each other but they do not substitute for each other. Good research practice requires that, to make sound research decisions, both sides should be considered. In a simulation study, the sampling variability of 2 popular effect-size measures (d and R ²) was examined. The variability showed that what is statistically significant may not be practically meaningful, and what appears to be practically meaningful could have been the result of sampling error, thus not trustworthy. Some practical guidelines are suggested for combining the 2 sources of information in research practice.     

Idea Generation and Exploration: Benefits and Limitations of the Policy Delphi Research Method

Researchers use the policy Delphi method to explore a complex topic with little historical context that requires expert opinion to fully understand underlying issues. The benefit of this research technique is the use of experts who have more timely information than can be gleamed from extant literature. Additionally, those experts place researchers in a specific moment, thus increasing the possibility of capturing change over time. One limitation of the policy Delphi is the difficulty in developing an accurate initial questionnaire to start the process. The purpose of this article is to identify benefits and limitations of this research method. Kathy K. Franklin is Associate Professor of Postsecondary and Private Sector Leadership at East Tennessee State University (ETSU), Franklin received her B.S. from the University of Alabama, M.B.A. from Middle Tennessee State University, and her Ed.D. from ETSU. Jan K. Hart is Assistant Director of the Medical Sciences Library at the University of Arkansas Medical School. Hart received her B.A. from the University of Kansas, M.L.S. from the University of Denver, and her Ed.D. from the University of Arkansas, Little Rock.Franklin and Hart study diverse research methodologies in the exploration and confirmation of theory.     

论茅盾的编辑思想及其当代意义

茅盾不仅是著名的文学家,也是出色的编辑家。表现在他具有强烈的社会使命意识,追求鲜明的期刊个性和强化读者意识,成功进行期刊商业化运作三个方面。在大众文化迅速普及的今天,茅盾的编辑思想对文学期刊及报纸副刊编辑的改革,编辑如何深入社会底层,深刻地把握时代脉搏,体察人文心态,恰当运用编辑技巧与方法,把握作者、读者及所编期刊的关系都具有积极的指导和借鉴意义。     

试论校本教育研究在基础教育课程改革中的独特作用

新一轮课程改革在全国迅速推开 ,基础教育领域里的各个方面发生了深刻的变化。进行校本教育研究 ,能使全体教师积极参与到课程改革与建设中 ,充分发挥广大教师在课程建设中的主体作用 ,确立教师在课程改革和建设中的主体地位 ,对推进新一轮基础课程改革具有积极深远的意义。