Databases Databases General Databases Comprehensive OR Core Databases

Databases

Databases � General Databases (Comprehensive OR Core Databases) � Specialized Databases (Subjects Specified Databases)

General Databases (Comprehensive OR Core Databases) � Medical ◦ Medline ◦ Embase � All Sciences ◦ Web of Sciences

Specialized Databases (Subjects Specified Databases) � Biological Abstracts � International Pharmaceutical Abstract � Psych. Info � CINAHL � Chemical Abstracts � Agricola � Econlite � AIDSline

Medline � By US National Library of Medicine � Bibliographic Data of Journal � papers of both clinical and preclinical studies. � Subject Coverage: All Specialties of Medicine � 60% of References contain Abstracts

Medline � Note that Medline, Pub. Med, Ovid Medline, Elsevier Medline, … all are the same & have the same database content but different Interfaces. � Also Index Medicus, Medlars & Medline Are the same, different generation of Medline.

Print versions of electronic databases � Index Medicus is the print version of MEDLINE � Excerpta Medica is the print version of EMBASE � Science Citation Index is the print version of Web of Science Database MEDLINE EMBASE Science Citation Index Printed Electronic version Since 1879 Since 1966 Since 1948 Since 1974

Web of Science � “Web of Science” is the database name provided by “Institute of Scientific Information” famous in our country as “ISI”. � The complete company name is Thomson Reuters ISI. � The Web of Sciences is the same database that we calculate the Journals Impact Factor from its data.

Web of Science � If a journal is in Web of Science, it means it should have Impact Factor & vice versa. � Don’t confuse Web of Sciences Journals with ISI Master list Journals !

The Journal Impact Factor � The Journal Impact Factor is calculated for those journals only which are indexed & included in Web of Sciences Databases, NOT more ! � The database which contain the Journal Impact Factors is Journal Citation Report abbreviated JCR.

What is Journal Impact Factor? The average citation frequency for articles published in a journal, or how many times, on average, during the study year the articles that appeared in the 2 preceding years of that journal received citations in other (ISI) indexed journals only.

Impact Factor Calculation Citations in the current JCR year to articles published in the previous two years divided by the number of articles published in the previous two years. IF= Citations in 2008 to articles published in 2006 + 2007 Total 2006 + 2007 Papers

Journal Impact Factors: � How is it calculated? E. g. , the 2009 Impact factor for the journal Cell = Number of times articles or other items published in Cell during 2007 & 2008 were cited in indexed journals* during 2009 –––––-––––––––––––––––––––––– Number of “citable” articles** published in Cell in 2007 & 2008 ~~~~~~~~~~~~~~~~~~~~~~~~ references in articles within the ~13, 000 journals indexed in Web of Science are counted; does not include citations that may cite the articles in Cell from book chapters, proceedings, or other journals that are not indexed in Web of Science *Only ** Citable articles are just research articles and reviews – not news articles, commentary, etc.

Journal Impact Factors: Calculating the 2009 Journal Impact factor for the journal Cell = That is: Cites in 2009 to items published in 2008 + 2007 = 9533 + 12554 = 22087 Number of items published in Cell in 2008 + 2007 = 343 + 366 = 709 Impact = Factor 22087 709 = 31. 152

2008 Impact Factors

2010 Journal Citation Reports Subject: Biochem & Molecular Biology Sorted by Impact Factor

Impact Factor

Consider, but do not be fooled by, the Journal Impact Factor (JIF) � JIF is determined by the frequency at which articles in that journal were cited � high impact journals have more prestige, but JIF depends on other things, like number of co -authors and indexing � non-English journals are at a disadvantage

Criticisms of Journal Impact Factors… � Only a limited subset of journals is indexed by ISI ◦ Only uses the articles cited by the ~13, 000 “ISI journals” ◦ Some disciplines are especially poorly covered � Biased toward English-language journals ◦ ISI has recently added several hundred non-English journals � Short (two year) snapshot of journal ◦ Some disciplines use older material more or take time to cite new research ◦ JCR now also includes the 5 -year data � Is an average; not all articles are equally well-cited

Criticisms of Journal Impact Factors… � Includes self-citations, that is articles in which the article cites other papers in the same journal � Only includes “citable” articles in the denominator of the equation, i. e. , articles and reviews ◦ Editors may skew IF by increasing the number of review articles, which bring in more citations (increases the numerator) ◦ Or by increasing the number of “news” items (e. g. , Science, general medical journals) , which are cited (appear in numerator) but not considered “citable” (and so aren’t in the denominator) � It is expensive to subscribe to the JCR

Conclusion � Journal Impact Factors will likely be around for a long time… the key is to understand how they work. � Don’t use Journal Impact Factors to evaluate individuals. Perhaps use h-index, instead? � Use multiple resources (Web of Science, Google Scholar, Psyc. Info, Scopus, etc. ) to find how many papers have cited your works.

H index Authors’ evaluation

Scientometrics Indexes � � � Number of Articles Total Citation per paper h-index g-index A-index e-index w-index Master curve Impact index m –quotient � � � � � Hgroup Group’s successive h-index (h 2) h(2)-index Ch-index h. SINGLE hg-index h- b index HI-index AR-index 24

Simple Measures �A ratio between the output of scientific research and its inputs is a most simple measure of scientific productivity. � The other commonly used measures are counting of the publications (Np : measures productivity; does not measure importance nor impact of papers) and citations to publications (Nc, tot : measures total impact; hard to count citations) � Citations per paper, i. e. , ratio of Nc, tot to Np. � Number of significant papers (q) – defined as number of papers with more than y citations; it eliminates the disadvantage of the earlier three. � Number of citations to each of the q most cited papers IKR RAO 6/3/2021 25

h-Index, for Evaluating Authors � Proposed by JE Hirsch as an index to quantify an individual's scientific research output Remember, Impact Factor is just for journals, though it’s often used to evaluate authors. � Combines an assessment of both quantity (number of papers) and quality (impact, or citations to these papers). � h-index is automatically calculated: ◦ Web of Science ◦ Scopus ◦ Publish or Perish (free download), based on data in Google Scholar

h-Index values � h-index can also be manually calculated for an author based on the number of papers authored and the number of times each paper has been cited. � As with other metrics, it’s best to compare h-index values within a discipline.

Determining h-index Manually

Finding a h-index value in Web of Science

Citation Report (h-index) from Web of Science

Finding a h-index value in Scopus

Citation Overview (h-index) from Scopus

Graph of h-Index from Scopus

Publish or Perish: (alternative search engine for Google Scholar)

Comparison of h-index Values from Several Sources for Several Authors From Scopus From Web of Science From Google Scholar via “Publish or Perish” 54 [193 docs] 55 [202 55 [381 docs] Chancellor Wise, 44 [178 docs] PM 51 [204 50 [333 docs] Author Robinson, GE Garfield, E 22 [211 docs] Pres. Hogan, MJ -- [1 doc] Pres. Easter, RA 23 [87 docs] 288 [815 docs] 6 [33 docs] 25 [107 docs] 45 [>1000 docs] 14 [65 docs] 38 [276 doc, many duplicates]

h-index : pros: combination, simplicity, easily understandable, � � Cons: not sensitive to high or low (non) cited articles, low resolution, discipline dependant 36

Advantages � The h-index is intended to measure simultaneously the quality and sustainability of scientific output, as well as, to some extent, the diversity of scientific research. � The h-index is much less affected by methodological papers proposing successful new techniques, methods or approximations, which can be extremely highly cited. � It is hard to inflate ones own h-index (for example by self citation. It relies on how a body of work is received over time. To manipulate an entire career is very hard. 37

Criticism are a number of situations in which h may provide misleading information about a scientist's output � The h-index is bounded by the total number of publications. This means that scientists with a short career are at an inherent disadvantage, regardless of the importance of their discoveries. For example, Évariste Galois' h-index is 2, and will remain so forever. Had Albert Einstein died in early 1906, his h-index would be stuck at 4 or 5, despite his being widely acknowledged as one of the most important physicists, even considering only his first four or five publications to that date. � There 38

Criticism � The h-index does not consider the context of citations. For example, citations in a paper are often made simply to flesh-out an introduction, otherwise having no other significance to the work. � h does not resolve other contextual instances: citations made in a negative context and citations made to fraudulent or retracted work. (This is true for other metrics using citations, not just for the hindex. ) � The h-index does not account for confounding factors. These include the practice of "gratuitous authorship", which is still common in some research cultures. 39

Criticism the h-index de-emphasizes singular successful publications in favor of sustained productivity, it may do so too strongly. Two scientists may have the same h-index, say, h = 30, but one has 20 papers that have been cited more than 1000 times and the other has none. Clearly scientific output of the former is more valuable. Several recipes to correct for that have been proposed, such as the g-index, but none has gained universal support � While 40

An Example (Data as on 2005) (Source: Nature) � Hirsch suggest that after 20 years in research, an h of 20 is a sign of success � If h = 40 after 20 years: outstanding scientists likely to be found only at the major research labs. � If h = 12 good enough to secure university tenure and fellowship of APS! Different disciplines have different levels! 41

Conclusion � Don’t use Journal Impact Factors to evaluate individuals. Perhaps use h-index, instead? � Use multiple resources (Web of Science, Google Scholar, Scopus, etc. ) to find how many papers have cited your works. � When considering where to publish, besides Journal Impact Factor of the journal also consider: • International reach • Where or if it’s indexed • Openly accessible? • Readership numbers • Subject appropriateness

Any questions? Email: ghalichi. l@iums. ac. ir