Impact Factors and the Central Limit Theorem: Why citation averages are scale dependent

Citation averages, and Impact Factors (IFs) in particular, are sensitive to sample size. Here, we apply the Central Limit Theorem to IFs to understand their scale-dependent behavior. For a journal of n randomly selected papers from a population of all papers, we expect from the Theorem that its IF fluctuates around the population average μ, and spans a range of values proportional to $\sigma /\sqrt{n}$, where σ² is the variance of the population's citation distribution. The $1/\sqrt{n}$ dependence has profound implications for IF rankings: The larger a journal, the narrower the range around μ where its IF lies. IF rankings therefore allocate an unfair advantage to smaller journals in the high IF ranks, and to larger journals in the low IF ranks. As a result, we expect a scale-dependent stratification of journals in IF rankings, whereby small journals occupy the top, middle, and bottom ranks; mid-sized journals occupy the middle ranks; and very large journals have IFs that asymptotically approach μ. We obtain qualitative and quantitative confirmation of these predictions by analyzing (i) the complete set of 166,498 IF & journal-size data pairs in the 1997–2016 Journal Citation Reports of Clarivate Analytics, (ii) the top-cited portion of 276,000 physics papers published in 2014–2015, and (iii) the citation distributions of an arbitrarily sampled list of physics journals. We conclude that the Central Limit Theorem is a good predictor of the IF range of actual journals, while sustained deviations from its predictions are a mark of true, non-random, citation impact. IF rankings are thus misleading unless one compares like-sized journals or adjusts for these effects. We propose the Φ index, a rescaled IF that accounts for size effects, and which can be readily generalized to account also for different citation practices across research fields. Our methodology applies to other citation averages that are used to compare research fields, university departments or countries in various types of rankings.     

美国科技博物馆展览开发中公众参与的研究及启示

展览开发是博物馆展览的基础问题,随着公众参与逐渐被提上研究议程,也促使我们去思考展览开发过程中如何引入公众参与。美国的科技博物馆展览开发已经建立了较为完善的公众参与体系:明确的参与者角色、系统的参与理念和阶段式的参与行为,已经获得了普遍的应用。借鉴美国博物馆的经验,我国博物馆展览的开发,应在构建展览评估体系的基础上,进一步了解和认识公众,拓展公众参与的方式,并不断寻求公众的声音。     

Dimensions: A competitor to Scopus and the Web of Science?

Dimensions is a partly free scholarly database launched by Digital Science in January 2018. Dimensions includes journal articles and citation counts, making it a potential new source of impact data. This article explores the value of Dimensions from an impact assessment perspective with an examination of Food Science research 2008–2018 and a random sample of 10,000 Scopus articles from 2012. The results include high correlations between citation counts from Scopus and Dimensions (0.96 by narrow field in 2012) as well as similar average counts. Almost all Scopus articles with DOIs were found in Dimensions (97% in 2012). Thus, the scholarly database component of Dimensions seems to be a plausible alternative to Scopus and the Web of Science for general citation analyses and for citation data in support of some types of research evaluations.     

液压与气压传动教学改革的探索与实践

《液压与气压传动》课程是机械类各专业的一门重要技术基础课。几年来通过优化整合教学内容,充分利用以计算机技术为基础的现代教学媒体,对课程内容、教学手段及教学方法的改革进行了探索与实践,提高了教学质量,较好地完成了教学任务。     

依法行政加强药品监督管理

贯彻《行政许可法》，依法加强药品监督管理，其根本目的是保证药品质量，保障人民用药安全有效。必须加强药监队伍建设，树立公正执法形象，构建健康有序的药品市场，实现药品监督执法的规范化、法治化。     

广西北部湾经济区财税政策效应的实证研究

通过分析广西北部湾经济区2000-2012年的统计数据,采用IS-LM模型对北部湾经济区的财税政策效应进行实证分析,发现存在财税政策较为固定单一等问题,应继续加强经济区政府部门体制改革及创新;继续加大对北部湾经济区的转移支付力度;积极推动适当调整税收制度的相关工作。     

鲁迅·魏晋风度·越文化——从唯美主义的角度

魏晋风度、越文化、唯美主义与鲁迅特定的个性气质、生命体验和文化视野相互渗透映发,从一个侧面造就了鲁迅精神世界的丰富深邃性,影响形成了他独特的文学主张和艺术风格。鲁迅以其真挚的生命体验和开阔的文化视野,打通中西古今界限,于传统文化、地域文化、世界艺术潮流之间兼容并蓄、颇富个性的择取与再创,体现了中西古今文化碰撞局面中现代文人的独特选择。这种创造性精神本身也成为亟待继承的文化传统,引发人们更多的思索。     

隐性分层下我校艺体类学生大学英语教学

隐性分层教学是针对学生个体差异,从学生实际情况出发,因材施教,使学生的不同学习需求得到满足,并获得成功体验的一种先进教学方法。高职高专艺体类学生大学英语水平的提高很大程度上取决于教师提供的条件和帮助,条件适当,帮助合理,学好英语就不成问题。     

全球化和信息化背景下高校思想政治理论课的教学困埔与教改策略

在全球化和信息化的时代背景下，我国大学生群体出现了政治信仰迷茫、理想信念模糊、价值取向扭曲、社会责任感缺乏等一系列不容忽视的问题，高校思想政治理论课教学正面临着严峻挑战。因此，研究高校思想政治理论课教学困境的成因，并寻求教改策略，是当前摆在广大思想政治理论课教师面前的一项重要课题。     

教师培训新形式:案例教学

对案例教学的内涵,案例研发以及案例教学的实施进行了探讨。