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.     

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.     

高校文科专业文献学教学的反思

针对文献学课程作为选修课常常受到文献检索等课程的挤压,作为必修课又受到教学对象主、客观两方面因素的制约的情况,提出文献学对于文史哲等专业的治学研究有指导作用,对于学生知识体系的建构和完善有着非同一般的意义,应该成为文科专业的基础课。改进文献学的教学现状,教师必须注意文献学观念的转变,注意与国学教育相融合,提升自己的学术含量,提高自己的文化品格,实现教学策略的调整。     

Elementary school children’s understanding of science: The implementation of an extracurricular science intervention

The promotion of students’ achievement and competence in the so-called STEM disciplines is one cornerstone of current educational research and practice. In particular, as early as elementary school, the fostering of an adequate understanding of science is a normative goal of science education. It facilitates students’ science learning and enables them to understand the nature and development of scientific knowledge. Based on the relevance of the promotion of young children’s understanding of science, a corresponding science intervention was recently developed and successfully evaluated in a first study under highly controlled conditions. The goal of the present study was to investigate the effectiveness of this intervention when implemented in practice. One hundred seventeen third- and fourth-grade students and 10 trained course instructors participated in this study. We applied a randomized block design with waitlist control groups and repeated measures. The results revealed that children assigned to the intervention compared with children assigned to the waitlist control group showed better inquiry-related methodological competencies (a better understanding of the scientific inquiry cycle and experimentation strategies) and a higher need for cognition. The findings point to the successful implementation of the intervention and are compared with the results of the first study.     

浅谈语文教学中的创新教育

语文教学中要培养学生的创新精神，就要充分挖掘学生的想象力，培养学生大胆设想、大胆尝试的能力。这些能力的培养就对老师的课堂教学提出了更高的要求，要大胆抛弃传统的教学模式，大胆创新。     

引导学生正确认识宗教问题

文章主要阐述在历文教学中要有针对性地解决学生提出的宗教问题，引导学生正确地看待宗教在社会主义社会的存在，认识宗教与迷信、邪教的区别，认识宗教与科学的关系。     

试从"自我"角度探求科技人性化之路径

文章初步尝试从人的自我的角度来探求科技人性化之路径:人要着眼于“善”假外物而促动科技的生命化和艺术化,用独立灵明的自我意识监控科技对自我之身心整体及其与外部自然和社会环境的关系过程,以大公大我推动科技在人类内部和谐的基础上发展。     

科学探究能力在科学教学中的培养

科学探究的方法和过程。既可以使初中生亲身体验到探究的乐趣。经历科学探究活动的过程，又可以使学生逐步提高探究能力，文章从多方面阐述了如何在中学生日常科学教学中。培养学生的科学探究能力。     

《孙子兵法》对企业商战的启迪

从当前我国企业面对国内国际竞争形势的十个方面,即企业战略、市场开拓、掌握市场竞争主动权、适应市场变化、居安思危、造势、企业领导人素质要求、领导艺术与团结职工等方面通过改革开放以来一些企业成败案例分析,联系《孙子兵法》中阐述的一些观点,可以清楚地看到孙子的光辉思想在今天对指导市场竞争、提高企业素质的点化作用与现实意义。