The Thomson Scientific Journal Selection Process
Thomson Scientific is committed to providing comprehensive coverage of the world's
most important and influential journals to meet its subscribers' current awareness
and retrospective information retrieval needs. Today Web of Science covers over
9,000 international and regional journals and book series in every area of the
natural sciences, social sciences, and arts and humanities.
But comprehensive does not necessarily mean all-inclusive. 1
Why Be Selective?*
It would appear that, in order to be comprehensive, an index to scientific
journal literature might be expected to cover all the scientific journals published.
This approach would be not only impractical economically, but as analyses of
the scientific literature have shown, unnecessary. It has been demonstrated
that a relatively small number of journals publish the bulk of significant scientific
results. This principle is often referred to as Bradford's Law. 2
In the mid-1930's S. C. Bradford realized that the core literature for any
given scientific discipline was composed of fewer than 1,000 journals. Of these
1,000 journals, there are relatively few with a very strong relevance to the
given topic, whereas there are many with a weaker relevance to it. Those with
a weak relevance to the given discipline or topic, however, typically have a
strong relevance to some other discipline. Thus, the core scientific literature
can form itself around various topics, with individual journals becoming more
or less relevant depending on the topic. Bradford understood that an essential
core of journals forms the literature basis for all disciplines, and that most
of the important papers are published in relatively few journals.3
* In order to evaluate a journal for possible coverage we must receive
at minimum three consecutive current issues, one at a time as they are published,
and/or free electronic access to the publication. Send print issues to Publication
Processing, 3501 Market Street, Philadelphia, PA 19104, USA.)
More recently, an analysis of 7,528 journals covered in the 2005 JCR® revealed
that as few as 300 journals account for more than 50% of what is cited and more
than 25% of what is published in them. A core of 3,000 of these journals accounts
for about 75% of published articles and over 90% of cited articles. Furthermore,
this core is not static. Its basic composition changes constantly reflecting
the evolution of scholarly topics. Our mission is to update journal coverage
in Web of Science by identifying and evaluating promising new journals, and
deleting journals that have become less useful.
The Evaluation Process
Journal evaluation and selection is ongoing at Thomson Scientific with journals
added to and deleted from the database as frequently as every two weeks. Each
year, Thomson Scientific's editorial staff reviews over 2,000 journal titles, and selects
around 10-12% of the journals evaluated for inclusion in the Thomson Scientific
database. Moreover, existing journal coverage in Thomson Scientific products
is constantly under review. Journals now covered are monitored to ensure that
they are maintaining high standards and a clear relevance to the products in
which they are covered. The journal selection process described here is applied
to all journals in Web of Science®, whether covered in Science Citation Index
Expanded™, Social Sciences Citation Index®, or Arts & Humanities Citation
Index®. Some special consideration is given in the evaluation of social science
and arts & humanities journals, particularly with regard to citation analysis.
These considerations are noted below.
Many factors are taken into account when evaluating journals for coverage, ranging
from the qualitative to the quantitative. The journal's basic publishing standards,
its editorial content, the international diversity of its authorship, and the
citation data associated with it are all considered. No one factor is considered
in isolation, but by combining and interrelating the data, the editor is able
to determine the journal's overall strengths and weaknesses.
The Thomson Scientific editors performing journal evaluations have educational
backgrounds relevant to their areas of responsibility as well as experience
and education in information science.
Basic Journal Standards
Timeliness of publication is a basic criterion in the evaluation
process. It is of primary importance. A journal must be publishing according
to its stated frequency to be considered for initial inclusion in the Thomson
Scientific database. The ability to publish on time implies a healthy backlog
of manuscripts essential for ongoing viability. It is not acceptable for a journal
to appear chronically late, weeks or months after its cover date.5
To measure timeliness we need to see three consecutive current issues, one after
another, as soon as they are published.
Timeliness is also essential for electronic journals. If the e-journal is publishing
distinct issues at a stated frequency, these issues should appear online in
a timely manner.
However, when an e-journal publishes articles one at a time rather than collecting
articles for release as an 'issue' we take a slightly different approach to
measuring timeliness. In these cases the editors look for a steady flow of articles
over several months time.
Thomson Scientific also notes whether or not the journal follows international
editorial conventions, which optimize retrievability of source articles.
These conventions include informative journal titles, fully descriptive article
titles and abstracts, complete bibliographic information for all cited references,
and full address information for every author.
English is the universal language of science at this time in history. It is
for this reason that Thomson Scientific focuses on journals that publish full
text in English or at very least, their bibliographic information in English.
There are many journals covered in Web of Science that publish only their bibliographic
information in English with full text in another language. However, going forward,
it is clear that the journals most important to the international research community
will publish full text in English. This is especially true in the natural sciences.
In addition, all journals must have cited references in the Roman alphabet.
Application of the peer review process is another indication of journal standards
and indicates overall quality of the research presented and the completeness
of cited references.6 It is also recommended that, whenever possible,
each article publish information on the funding source supporting the research
presented.
Editorial Content
As mentioned above, an essential core of scientific literature forms the basis
for all scholarly disciplines. However, this core is not static--scientific
research continues to give rise to specialized fields of studies, and new journals
emerge as published research on new topics achieves critical mass. Thomson Scientific
editors determine if the content of a journal under evaluation will enrich the
database or if the topic is already adequately addressed in existing coverage.
With an enormous amount of citation data readily available to them, and their
daily observation of virtually every new scholarly journal published, Thomson
Scientific editors are well positioned to spot emerging topics and active fields
in the literature.
International Diversity
Thomson Scientific editors look for International Diversity
among the contributing authors and the journal’s editors and Editorial Advisory
Board members. This is particularly important in journals targeting an international
audience. Today’s scientific research takes place in a global context and an
internationally diverse journal is more likely to have importance in the international
community of researchers.
As the global distribution of Web of Science expands into virtually every
region on earth, the importance of regional scholarship to
our emerging regional user community also grows. Selection criteria for regional
journals are the same as for international journals although citation analyses
play a somewhat different role in the outcome. For example, the importance of
the regional journal would be measured more in terms of the specificity of its
content. Will it enrich our coverage of a particular subject or provide studies
with a specific regional perspective?
Many excellent regional journals target a local rather than an international
audience. Therefore, the emphasis on extensive international diversity is less
than for internationally focused journals.
All regional journals selected must be publishing on time, have English-language
bibliographic information (title, abstract, keywords), and be peer reviewed.
Cited references must be in the Roman alphabet.
Citation Analysis
The Thomson Scientific evaluation process is unique in that Thomson Scientific
editors have a wealth of citation data available to them. The importance of
interpreting and understanding these data correctly cannot be emphasized too
strongly. Using quantitative citation data to measure impact is meaningful only
in the context of journals in the same general discipline. For example, smaller
fields like crystallography do not generate as many articles or citations as
do larger fields such as biotechnology or genetics. Likewise, in some areas,
particularly in the arts and humanities, it may take a relatively long time
for an article to attract a meaningful number of citations. But in other areas,
such as the life sciences, it is not unusual for citations to accrue rapidly
and peak after two or three years.7 These facts must be taken into
consideration if citation data are to be used correctly.
Citation analyses takes place on at least two levels. We look for citations
to the journal itself, as expressed by Impact Factor and/or total citations
received. We also examine the citation record of the contributing authors, a
useful study in evaluating new journals where a citation history at the journal
level does not yet exist.
Likewise, established journals that are not covered are often re-evaluated.
These journals can experience new growth in citation impact resulting from changes
such as translation into English, change in editorial focus, change in Publisher,
medium, etc.
Because Thomson Scientific captures all cited references from each of the 9,300
journals covered, citation information is available on journals not covered
as well as those that are covered.
Self-citation rates are also taken into consideration. The self-cited rate relates
a journal’s self-citations to the number of times it is cited by all journals,
including itself. For example, journal X was cited 15,000 times by all journals,
including the 2,000 times it cited itself. Its self-cited rate is 2/15 or 13.3%.
A high volume of self-citation is not unusual or unwarranted in journals that
are leaders in a field because of the consistently high quality of the papers
they publish, and/or because of the uniqueness or novelty of their subject matter.
Ideally, authors reference the prior publications that are most relevant to
their current results, independently of the source journal in which the work
was published. However, there are journals where the observed rate of self-citation
is a dominant influence in the total level of citation. For these journals,
self-citation has the potential to distort the true role of the title as a participant
in the literature of its subject. 8
Eighty per cent of all journals listed in the JCR Science Edition have self-citation
rates less than or equal to 20%. This shows that self citation is quite normal
for most journals and is expected. Significant deviation from this normal rate,
however, prompts an examination by Thomson Scientific to determine if excessive
self-citations are being used to artificially inflate the Impact Factor. If
we determine that self-citations are being used improperly, the journal’s Impact
Factor will not be published and the journal may be considered for deselection
from the Web of Science.
Social Sciences
All social science journals undergo the same thorough evaluation as journals
in the natural sciences. Publishing standards, editorial content, international
diversity, and citation data are all considered. Standard citation metrics are
analyzed while keeping in mind that overall citation rates in the social sciences
are generally lower than those in the natural sciences.
Regional studies have special importance in the social sciences as topics of
local rather than global interest are often the subject of scholarly research.
Arts & Humanities
Publishing standards, including timeliness, are important in the evaluation
of arts and humanities journals. Citations patterns in the arts and humanities,
however, do not necessarily follow the same predictable pattern as citations
to social sciences and natural sciences articles. In addition, arts and humanities
journal articles frequently reference non-journal sources (e.g., books, musical
compositions, works of art and literature). English-language text is not a requirement
in some areas of A&H scholarship where the national focus of the study precludes
the need for it; for example, research in regional literatures.
Electronic Journals
As stated earlier, the basic mission of Thomson Scientific is to provide access
to the world's most important and influential journals regardless of the media
in which they are published.
Publishing Standards, Editorial Content, International Diversity, and Citation
Analysis are all considered when evaluating a purely electronic journal.
Evaluating the timeliness of publication of an e-journal may require a somewhat
different approach. If the e-journal is publishing distinct issues the Thomson
Scientific editor looks for the appearance of these in a timely manner. However,
when an e-journal publishes articles one at a time rather than collecting articles
for release as an 'issue' the editor simply looks for a steady flow of articles
over several months time.
The Format of Electronic Journals is extremely important
to Thomson Scientific. Following are a set of guidelines for Electronic Journal
formats. Following these guidelines helps insure correct citation of articles
and reduces the possibility of ambiguity in citation of articles.
Insure that it is easy to identify the following elements:
- Journal Title
- Year of publication
- Volume and/or Issue Number (if applicable)
- Article Title
- Page Number or Article Number (one or the other is required; article
number should not be the DOI) If your journal has page numbers and article
numbers, list them separately and not merged
- together. EXAMPLE: Art. #23, pp. 6-10 and not 23.6-23.10
- Authors names and addresses
- Label all article identifiers such as DOIs, PIIs and Article Numbers
- A complete table-of-contents for each issue that includes the page/article
number for each article (unless journal is being published as single articles)
Labeling these identifiers in both source articles and in citations helps
insure their proper use by those referencing the article and correct labeling
by abstracting and indexing firms such as Thomson Scientific.
- Each article must be assigned a unique page number or article number (whichever
numbering scheme is being used) within any one given issue. Additionally,
article numbers must be unique within an entire volume number. If the same
article numbers are repeated in each issue within a volume, ambiguities will
result when citing the original article. A citation to V 20, art. 1, May 2002,
(even when adding the author's name), would be difficult to find if V 20,
art. 1 June 2002 also exists. Avoid duplication of article numbers. References
to Your Electronic Journal. Instruct authors to include the following information
when citing your e-journal:
- Journal title (use one standard abbreviation for your journal; avoid acronyms
that may be confused with other titles)
- Volume number (if applicable)
- Issue Number (if applicable; within parenthesis)
- Page number and/or article number (clearly identifying the article number
as such)
- Year of publication
How to Recommend Journals or submit a journal for evaluation
Thomson Scientific welcomes suggestions and recommendations for coverage. If
you would like to recommend a journal for evaluation, please follow the links
below and provide all necessary information as well as access to your journal
either electronically or in print.
Recommend a journal for coverage in Web of Science at http://scientific.thomson.com/forms/isi/journalrec/.
Submit a journal for evaluation for Web of Science at http://scientific.thomson.com/forms/isi/journalsubmission/.
This essay was prepared by James Testa, Senior Director,
Editorial Development & Publisher Relations, Thomson. Special thanks
to Editorial Development staff members Katherine Junkins , Maureen Handel, Mariana
Boletta, Ryan Joyce, Kathleen Michael, Rodney Chonka, Chang Liu, and Luisa Rojo
for their critical reading and comments. .
1. Garfield, E., How ISI Selects Journals for Coverage: Quantitative and Qualitative
Considerations. Current Contents, May 28, 1990.
2. Garfield, E., Citation Indexing (New York: John Wiley & Sons, 1979)
3. Ibid.
4. Garfield, E., The Significant Scientific Literature Appears in a Small Core
of Journals. The Scientist V10 (17), Sept. 2, 1996.
5. Garfield, E., How ISI Selects Journals for Coverage: Quantitative and Qualitative
Considerations. Current Contents, May 28, 1990.
6. Ibid.
7. Ibid.
8. McVeigh, M., Journal Self- Citation in the Journal Citation Reports – Science
Edition. 2002. http://scientific.thomson.com/free/essays/journalcitationreports/selfcitation2002/.
