H-Index and How to Improve It? REVIEW ARTICLE
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DSJUOG 10.5005/jp-journals-10009-1446H-index and How to Improve it? REVIEW ARTICLE H-index and How to Improve it? Izet Masic ABSTRACT the first time is mentioned by the American researcher The h-index is an index that attempts to measure both the Eugene Garfield, in an article published in the journal of productivity and citation impact of the published work of a ‘Science’ in 1955, which was the basis for the publication scientist or scholar. The index is based on the set of the of the science citation index (SCI) in 1961. Today, the scientist’s most cited papers and the number of citations that journal impact factor is extracted from publication under they have received in other publications and on the distribution the title journal citation reports (JCR), which is produced of citations received by a given researcher’s publications. The h-index is important for individual users as well as scientific by Thomson Reuter’s publishers. The best measure of research institutions, universities and main journal editors. the importance of the journal is its echo factor, which There are a lot of methods to improve your h-score. It takes shows how many articles published in it are cited.7,8 For a lot of work and to promote papers and journals, but it is all example, if the journal has impact factor from 0.10 to part of developing as a researcher, working together with your 0.30 in a certain period, it means that on average every community and improving communication methods. tenth to every third article published in the journal is Keywords: H-index, Impact, Research. cited once. In other words, the impact factor tells us how How to cite this article: Masic I. H-index and How to Improve it? much the journal is used, or how much it is important Donald School J Ultra sound Obstet Gynecol 2016;10(1):83-89. for the scientists. Source of support: Nil Evaluation of scientific productivity and assessment of the published articles of researchers and scientists Conflict of interest: None can be made through the so-called h-index.2-4,6,8 Index is calculated on the basis of the list of publications ranked INTRODUCTION in the order of time when they are quoted. The value of Evaluation of the quality and relevance of articles, after this index is equal to the number of documents (N), in they have been accepted and published as scientific the list that have N or more citations. papers, which should be the result of serious research The quality of published results of a scientific work work, relies mainly on the qualified members of the largely depends on the knowledge resources that have academic community, who are of the same or similar been used in the preparation of it, which means that it professional interests.1-6 Being a part of the academic should be considered to serve the purpose and the very community, we often encounter terms, such as indexing, relevance of the information used for it. The relevance of and citations. According to the Tibor Toth, who wrote in data for research specifically described and contributes an article published on the website of open encyclopedia the search for resources. of information: Indexing is a term that derives from the In the ranking of the journal in terms of their concept of index of publications, such as Index Medicus, quali tative contributions to science research valuable Science Citation Index and Current Contents.2,3 contribution brings SCImago Journal and Country Rank, The assessment of the achievement of every scientist, as Internet portals that publish indicators of journals and thus indirectly determining his reputation in the from countries around the world. This instrument for scientific community of these publications, especially measuring the scientific competitiveness on a global journals, is done through the so-called impact factor.7 scale was developed based on the source of information Impact factor shows how many times a scientific article contained in the Scopus database. in a specific journal receives average number of quotes (citations) (Graphs 1 and 2). The idea of impact factor for H-INDEX The h-index is an index that attempts to measure both the productivity and citation impact of the published work of Professor a scientist or scholar. The index is based on the set of the Faculty of Medicine, University of Sarajevo, Bosnia and scientist's most cited papers and the number of citations Herzegovina that they have received in other publications. The index Corresponding Author: Izet Masic, Professor, Faculty of can also be applied to the productivity and impact of a Medicine, University of Sarajevo, Bosnia and Herzegovina as well as a group of scientists, such as a department or e-mail: [email protected] university or country.4 Donald School Journal of Ultrasound in Obstetrics and Gynecology, January-March 2016;10(1):83-89 83 Izet Masic Graph 1: Impact factor journal ranking9 journal editors. As we saw, there is a way to calculate the values of h-index for individual authors, for every article, institution, publishing house or journal. Any of these users try to maximize the value of their h-index because it represents a direct evaluation of the quality of their work. The h-index is and attempt to measure productivity and the impact of the published scientific work of a scientist or student. As such it is applicable to a group of scientists, a country or scientific institution. When calculation the h-index for one author, or a single journal, it reflects the number of published works as well as the number of quotes taken from individual publications. Despite the fact that its relatively new (it was 10,11 Graph 2: H-index of the four most cited journals des cribed for the first time in 2005), the h-index has become an important measure (Figs 1 and 2) of career The index was suggested in 2005 by Jorge E Hirsch, development.4 as a tool for determining theoretical physicists' relative quality and is sometimes called the Hirsch index or Weaknesses of the h-index13 Hirsch number.4 The index is based on the distribution of citations Critics of the metric suggest it is limited in the following received by a given researcher's publications. Hirsch ways: writes: A scientist has index h if h of his/her number of • It counts a highly-cited paper regardless of why it is papers (Np) have at least h citations each, and the other being referenced, e.g. for negative reasons (Np−h) papers have no more than h citations each. • It does not account for variations in average number In other words, a scholar with an index of h has of publications and citations in various fields (some published h papers each of which has been cited in other traditionally publish and cite less than others) papers at least h times. Thus, the h-index reflects both • It ignores the number and position of authors on a the number of publications and the number of citations paper per publication. The index is designed to improve upon • It limits authors by the total number of publications, simpler measures, such as the total number of citations so shorter careers are at a disadvantage or publications. The index works properly only for • It has relatively low resolution in that many scientists comparing scientists working in the same field; citation end up in the same range since it gets increasingly conventions differ widely among different fields.4 difficult to increase the h-index the higher it gets (an The h-index is important for individual users as well h-index of 100 corresponds to a minimum of 10,000 as scientific research institutions, universities and main citations). 84 DSJUOG H-index and How to Improve it? Fig. 1: H-index according to the authors from particular countries12 Fig. 2: Available at: https://wiki.oulu.fi/display/tor/1.3.1.7.10+SCImago+Journal+and+Country+Rank (May 02, 2014) It, like all metrics, is based on data from the past published over number of (n) years, the number of and may not be a valid predictor of future performance. citations (Nc) for each paper (j), the journals where the However, in a follow-up publication Jorge Hirsch papers were published, their impact parameter, etc. demonstrated that the h-index is better than other indi- (Figs 3 and 4). This large amount of information will be cators (total papers, total citations, citations per paper) at evaluated with different criteria by different people.4 13 predicting future scientific achievement. Some authors Google Scholar Citations provide a simple way for consider that the time dependence of the h-index is better authors to keep track of citations to their articles. You can than h-index alone, because it is important to describe check who is citing your publications, graph citations over the expected career evolution of a scientist's work or of time, and compute several citation metrics.16 The h-index 14 a journal's production in a fixed year. can be calculated using Google Scholar. In the Web of Science h-factor only scientific articles How to Calculate h-index? published in journals which have ISI-recognition The publication record of an individual and the citation (determined by Thomson-Reuters) are considered citeable record clearly are data that contain useful information. (so not articles in other journals, chapters in books, etc.). That information includes the number of papers (Np) In the Scopus h-factor a larger pool of journals is included, Donald School Journal of Ultrasound in Obstetrics and Gynecology, January-March 2016;10(1):83-89 85 Izet Masic citation can also increase h-index.18 Double publication of the some paper for a conference, and later with slightly different name in a paper, can also increase citation index.