impact factor of journals
DESCRIPTION
TRANSCRIPT
Dr. Pinki Insan
Indira Gandhi University Meerpur Rewari
IMPACT FACTOR OF JOURNALS
JOURNAL IMPACT FACTOR WAS INVENTED BY
THOMSON REUTER (ISI). ISI was founded by Eugene Garfield
in 1958
Journal Impact Factor is from Journal Citation Report (JCR),
a product of Thomson ISI
(Institute for Scientific Information).
Eugene Garfield
The Journal Impact Factor is defined as the number of
citations in current year to items published in the
previous two years, divided by the total number of items
published in those same two years.
Basic Definitions IMPACT = EFFECT
CITATION= ENTRIES IN A LIST OF REFERENCES AT THE END OF AN ARTICLE, CHAPTER, BOOK, ETC
DATABASE=COLLECTION OF
RECORDS ABOUT, FOR EXAMPLE, ARTICLES PUBLISHED IN A PARTICULAR FIELD.
The Impact Factor for a given year is defined as the total
number of citations received in that year to articles published in the previous two years divided by the total number of citable
items (source items) published by the journal in those two
years.
Impact factor is the ratio of number of citations received by source items in a particular year to the number of source items published over a fixed period of time in a particular periodic publication, say a journal Source items: original articles, editorials letters short communications report of meetings correction, notes review articles etc.
Timing The Impact Factors for a
given year are published annually in
September/October of the following year in the
Journal Citation Reports (JCR).
An Impact Factor of 1.0 means that, on average, the articles published one or two year ago have been cited one time.
An Impact Factor of 2.5 means that, on average, the articles published one or two year ago have been cited two and a half times.
The impact factor for a journal is calculated based on a three-year period, and can be considered to be the
average number of times published papers are cited
up to two years after publication.
Calculation For example, the impact factor 2010 for a journal would
be calculated as follows: A = the number of times articles published in 2008-9
were cited in indexed journals during 2010 B = the number of articles, reviews, proceedings or
notes published in 2008-2009 Impact factor 2010 = A/B
The impact factor 2009 will be actually published in 2010, because it could not be calculated until all of the 2009 publications had been received. Impact factor 2010 will be published in 2011
Calculating the BMJ’s impact factor for 2003
Computation of Journal Impact Factor
following key points related to Journal Impact factor
Journal Impact Factor can not be calculated for new journals. I mean “the impact factor of a journal is calculated by dividing the number of current year citations to the source items published in that journal during the previous two years”, hence impact factor can be calculated after completing the minimum of 3 years of publication.
••••Journal Impact Factor will be a quotient factor only and will not be a quality factor.
••••Journal Impact Factor will not be related to quality of content and quality of peer review, it is only a measure of the frequency with which the "average article" in a journal
has been cited in a particular year or period. ••••Journal which publishes more review articles will get
highest impact
COMPUTATION
C1+C2
S1+S2C1 denotes the number of citations received by S1
source items in the year Y
C2 denotes the number of citations received by S2 source items in the year Y
S1 denotes the number of source items published in the journal J in the year Y-1.
S2 denotes the number of source items published in the journal J in the year Y-2
Example Suppose the journal j has published 32
and 36 sources in 2007 and 2008 respectively. These source items have received respectively 40 and 28 citations in 2009.Now the impact factor of the journal j will be
40+28/32+36=1
Features
It is not a constant like the specific gravity of water
The number is expressed up to three digits after decimal in JCR e. g. 2.319
It is year- specific. It is database specific. Value of impact factor generally lies
between 0 and 50.
It varies from subject to subject.
The impact factor indicates the
standing of the journal in the world.
The impact factor may be considered as an indication of the quality of the journal in most cases.
Uses Selection of journals for library:
standing of journals in the world.
Discontinuation of journals: Journals figuring at the bottom of the ranked list are choosen.
Palacing a paper: journal citation report.
‘Abstracts are not defined as source items
and so even if they only attract a few citations,
there is a benefit to the Impact Factor’
The impact factor is only one of three standardized
measures created by the Institute of Scientific Information
(ISI) which can be used to measure the way a journal
receives citations to its articles over time.
The best way to keep track of who is citing you.
•Have a very complete copy of your publications
•Use Web of Science and Google Scholar. They will produce overlapping and unique results
•The Impact Factor is a an attempt to ensure the impact a journal has.
•It is designed to “scale” the number of times a journal has been cited.
•The older an article is, the more opportunities it has to have been cited.
•Some disciplines have more people working in
them (child psychology vs. demography; surgery vs. mycology)
JCR Home Page
Before starting, click on Information for New Users and read “Using the JCR Wisely.”
Science and Social Science editions must be searched separately
Journal Search Screen
You can search by Full Journal Title, Journal Abbreviation, Title Word, or ISSN. Select Title Word from the menu.
JOURNAL SUMMARY LIST
Click on title link to display full record.
Source Data
Tallies the number of original research and review articles published in the current year (2005) Also tallies the number of references published by the selected journal in the current year Other Items = document types not included in the number of citable items published by this journal (e.g.
letters, news items, editorials, etc.)
Review articles are often more highly cited than original research articles: consider a journal’s source data by document type.
Cited Journal List
A list of journals which have cited Atmosphere-Ocean within 2004
Publication year of cited article.
References to all older articles.
Citing Journal List
A list of journals that Atmosphere-Ocean has cited within 2004.
The publication year of the articles being cited
Impact Factor Trend Graph
Examine Subject Categories