Post on 08-May-2015
description
Bibliometrics :
Essential Concepts and Tools
Elaine M. Lasda BergmanBibliographer for Social Welfare and Dewey ReferenceDewey Graduate Library
Scholarly communication: tracing the history and evolution of ideas from one scholar to another
Measures the scholarly influence of articles, journals, scholars
What is bibliometrics?
Eugene Garfield: “father of citation analysis” developed the first bibliometric index tools
Citation indexes and Journal Citation Reports “ISI Indexes”: Science Citation Index, Social
Science Citation Index, Arts and Humanities Index
Better coverage on hard sciences than on social sciences and worse still on humanities
The birth of citation analysis
Citation count Impact Factor Immediacy Index Citation Half-Life
Garfield’s metrics
Number of times cited within a given time period Author Journal
Does not take into account Materials not included in citation database Self citations
Citation count
Measures “impact” of a journal (not an article) within a given subject
Formula is a ratio: Number of citations to a journal in a given year
from articles occurring in the past 2 years Divided by the number of scholarly articles published in the journal in the past 2 years
Impact factor
Cannot be used to compare cross disciplinary (per Garfield himself) due to different rates of publication and citation
Two year time frame not adequate for non-scientific disciplines
Coverage of some disciplines not sufficient in the ISI databases
Is a measure of “impact” a measure of “quality”?
Concerns with impact factor
What it’s supposed to measure: how quickly articles in a given journal have an impact on the discipline
Formula: the average number of times an article in a journal in a given year was cited in that same year
Immediacy index
What it’s supposed to measure: duration of relevance of articles in a given journal
Formula: median age of articles cited for a particular journal in a given year
Citation Half-Life
Twenty first century tools
Eigenvector analysis: “The probability that a researcher, in documenting his or
her research, goes from a journal to another selecting a random reference in a research article of the first journal. Values obtained after the whole process represent a ‘random research walk’ that starts from a random journal to end in another after following an infinite process of selecting random references in research articles. A random jump factor is added to represent the probability that the researcher chooses a journal by means other than following the references of research articles.” (Gonzales-Pereira, et.al., 2010)
Influence of Google Page Rank
Sources Using ISI Data
Journal Ranking.com uses ISI data and eigenvector (PageRank) algorhythm to create one’s own categories Can assign different weights to citations from
the same journal, the same category and from other categories or only whithin a specific list
Not updated since 2005 http://libguides.library.albany.edu/content.php?
pid=60086&sid=441804
Journalranking.com
Uses ISI data Similar to PageRank Listed in JCR as of 2009 Eigenfactor Score :
Influence of the citing journal divided by the total number of citations appearing in that journal
Example: Neurology (2006): score of .204 = an estimated 0.2% of all citation traffic of journals in JCR (Bergstrom & West, 2008).
Larger journals will have more citations and therefore will have larger eigenfactors
Eigenfactor.org http://libguides.library.albany.edu/content.php?pid=60086&sid=441804
From Eigenfactor: measure of prestige of a journal Average influence, per article of the papers on a
journal Comparable to the Impact Factor Corrects for the issues of journal size in the raw
Eigenfactor score Neurology’s 2006 article influence score = 2.01.
Or that an avg. article in Neurology is 2X as influential as an avg. article in all of JCR
Article Influence Score
Provides “quick and dirty” articles on hot researchers, trending research topics, institutions and journals
Much on this site (in-cites, etc) are now parts of analytical products being sold byThompson; no longer free
There are still some good articles, but not searchable, hit or miss information
http://sciencewatch.com/dr/sci/11/
ScienceWatch
Google Scholar Scopus
New sources for citation information
Review panel, i.e., quality control Bigger field than ISI: covers all the journals
in WoS and more Strongest in “hard”sciences”, ostensibly
improved social science coverage, arts and humanities: are “getting there”
Algorithmically determined with human editing
Scopus: alternate database of citation data
No rhyme or reason to what is included Biggest source of citation data Foreign language sources Sources other than scholarly journals Entirely algorithmically determined, no
human editing
Google Scholaralternate database of citation data
SNIP SJR/SCIMago Author Evaluator
Scopus analytics
Journal Ranking based on citation analysis with adjustments for the frequency of citations of the other journals within the field (the field is all journals citing this particular journal)
SNIP is defined as the ratio of the journal’s citation count per paper and the citation potential in its subject field. (Moed, 2009)
http://www.scopus.com/home.url
SNIP (Source Normalized Impact Per Paper)
What it’s supposed to measure: “current “average prestige per paper”
SCImago website uses journal/citation data from Scopus, and is also available from scopus db
Formula: citation time window is 3 years instead of 2 like JIF
Corrections for self citations Strong correlation to JIF
SJR:SCImago Journal Rank
Prestige factors include: number of journals in db, number of papers from journal in database, citation numbers and “importance” received from other journals: size dependent: larger journals have greater prestige values
Normalized by the number of significant works published by the journal: helps correct for size variations
Corrections made for journal self citations
SCImago Journal Rank
Breakdown of documents by source H-index Citations per year (graph)
Scopus Author Evaluator
Publish or Perish CIDS
Google Scholar
Provides a variety of metrics for measuring scholarly impact and output.
More useful for metrics on authors than journals or institutions
Uses Google Scholar citation information Useful for interdisciplinary topics, fields relying
heavily on conference papers or reports, non-English language sources, new journals, etc.
Continuously updated since 2006
Publish or Perish
Basic metrics: # papers, #citations, active years, years since first
published, average #of citations per paper, average # of citations per year, average # citations per author, etc.
Complex metrics H index (and its many variations, mquotient, g-index
(corrects h-index for variations in citation patterns), AR index, AW index
Does not have any corrections for SELF CITATIONS
Publish or Perish Metrics
Measures output of authors for prestige and influence
Similar to PoP Corrects for Self-Citations Uses Google Scholar data
CIDS
Citations per year, h-index, g-index, total citations, avg cites per paper, self citations included and excluded, etc.
http://cids.di.fc.ul.pt/cids_3_0/info.php?acc=25201514041114103161
CIDS metrics
Metric based on usage, citation and bibliographic data
Uses its own datbases of documents/metadata/reference, users & authors, “usage events” and citations
Project seems to be dead?
Mesur
Don’t measure an individual journal’s impact by the metrics for the entire journal
Cluster of years of citations Negative citations A few high impact citations or a lot of low
impact ciations Source of citing documents
Foreign, conference proceedings, traditional
Considerations