Tag Archives: google scholar

Tools for Ranking Journals by Impact

Posted on by

Many considerations should factor into a well-made decision about which journal(s) an author should target for manuscript submission. (For more info, see the MSK Library’s Support for Authors LibGuide.) 

As they explore their options, it’s often useful for authors to get a sense of how reputable a particular journal title is based on how this journal ranks – in terms of impact – versus other journals within the same discipline. In general, journal impact metrics are generated using a mathematical algorithm that is largely based on article citation counts over a pre-specified time period. Citation count data can provide some indication of a journal’s influence and reach, particularly when considered relative to other journals.

Below are three tools (two subscription databases available via the MSK Library and one free online search engine) that can be used to generate journal impact ranking information that can aid with the journal selection process.

Journal Impact FactorsTM – and the Journal Citation Reports (JCR) rankings that they lead to – are generated using two years-worth of article citation data compiled in Clarivate’s Web of Science database. This metric has been around for over 50 years, and was developed by the originator of the citation analysis concept, Eugene Garfield, who is often considered the grandfather of information science and scientometrics. 

See more details on how the Journal Impact FactorTM is calculated.

Elsevier generates it own impact metric, called the CiteScoreTM, by using the citations to articles, reviews, conference papers, book chapters and data papers published over a four-year publication window. Similar to Clarivate, Elsevier can generate these metrics because the data needed for the calculations is available from its flagship Scopus database.

See more details on how the CiteScoreTM is calculated.

Google Scholar, although not a structured database populated with records that have standard fields (as is the case in JCR and Elsevier’s Scopus Sources) still collects citation data that it compiles via the Google Scholar search crawler. It then uses citation data to generate an h-index type metric for the entire journal, as opposed to the usual use of the h-index to evaluate the productivity of an individual researcher. Google Scholar h5 metrics are calculations based on the citation count to published items from the last five complete calendar years.

See more details on how Google Scholar h-based metrics are calculated.

Be sure to check out the MSK Library’s Measuring Research Impact class and the Evaluating Journal Quality class if you have questions, or Ask Us! 

Checking to What Extent PubMed and MEDLINE Index a Journal

Posted on by

Understanding the extent to which a particular database indexes the contents of a journal is a crucial step towards maximizing the visibility and reach of your published work(s).

Although social media and other marketing channels have definitely helped with getting the word out about new research in scholarly publishing, the reach of bibliographic indexes in terms of providing access to content beyond an individual author’s personal and professional networks is still very significant.

There are a few factors that impact the visibility and reach of a literature database:

1) Public access versus commercial databases

Content that everyone has access to because it is not stored behind a paywall, regardless of how well-funded their institution is or if they are affiliated with a research library or not, has the potential of reaching a wide range of audiences across the globe. In the case of PubMed, for example: “On an average working day approximately 2.5 million users from around the world access PubMed to perform about 3 million searches and 9 million page views.”   

2) Syndicated/leased/shared versus proprietary content

“Syndicated content is content that is published on multiple sites beyond the source, which broadens its reach and visibility”. There are some databases, like MEDLINE, whose content is leased to other database vendors and  can be searched (in whole or in part) in other resources. For example, MEDLINE content is included in EMBASE, CINAHL, and Cochrane Library. Having a journal indexed in both MEDLINE and PubMed, therefore, increases the potential for the contents of that journal to be discovered by searchers of databases beyond NLM’s PubMed’s free search interface.  For this reason, it is helpful to understand the difference between PubMed and MEDLINE and how each of these resources is put together.

3) “Surface” versus “deep” web indexing by search engines

Another important question to ask of an online database is: Do regular web search engines, like Google, “see” the contents of this database? In the case of the vast majority of database resources on the Internet, the standard World Wide Web search engines generally stop at the front door of the database tool and do not index the actual contents within the database. In the case of PubMed, however, Google actually “crawls” the records contained within the database, increasing their findability by Google Scholar searchers who may never search the PubMed database via its native interface.

From Vine R. Google Scholar. J Med Libr Assoc. 2006 Jan;94(1):97–9. PMC1324783:

“Much of Google Scholar’s index derives from a crawl of full-text journal content provided by both commercial and open source publishers. Specialized bibliographic databases like OCLC’s Open WorldCat and the National Library of Medicine’s PubMed are also crawled. Since 2003, Google has entered into numerous individual agreements with publishers to index full-text content not otherwise accessible via the open Web. Although Google does not divulge the number or names of publishers that have entered into crawling or indexing agreements with the company, it is easy to see why publishers would be eager to boost their content’s visibility through a powerhouse like Google.”

In short, selecting a journal to publish in that is indexed in PubMed, as well as, in MEDLINE, gives your manuscript a good head start towards achieving maximum international reach and visibility.

Follow these steps to determine whether a journal is indexed in PubMed alone, in both PubMed and MEDLINE, or in neither:

Click on the “Journals” link of the PubMed homepage or go directly to the NLM Catalog to search for Journals referenced in the NCBI Databases. Once you bring up a catalog record for a journal of interest, click on the title to open the full record where you can confirm a journal’s MEDLINE “Current Indexing Status”.

Below are examples of the indexing status information provided in NLM Catalog records:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Questions?  Ask Us at the MSK Library!