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