Citation Searching: Journal Rankings and Impact Factors

Though controversial, journal rankings and impact factors have become increasingly important in the academic world. Scholars use them to determine the best venues for publication. Tenure committees look at them to assess the relative impact of a tenure candidate's work. Library administrators look at them to decide which journal subscriptions are the most important.

Journal Citation Reports (JCR) is a citation tool for evaluating a journal’s IF.  It is owned by ThomsonReuters (the same company that owns Web of Science) and comes in two editions: Science or Social Sciences. Impact factors are calculated yearly starting from 1975. JCR uses both the Eigenfactor® Score and the Article Influence® Score in order to assess the influence of a journal in relation to other journals. The last five years of citation activity are counted.   Eigenfactor metrics are available from JCR for years 2007 and later. For a more in depth explanation of Eigenfactor and Article InfluenceScores click here: http://www.eigenfactor.org/whyeigenfactor.php

To perform a journal ranking search using Eigenfactor, click here: http://www.eigenfactor.org/projects/journalRank/journalsearch.php 

this includes Article Influence Score too.

JCR also offers a metric indicator called the Immediacy Index. The Immediacy Index is the average number of times an article is cited in the year it is published.  This index attempts to quantify the importance of recent articles in particular journals.  For a discussion on the usefulness of this index click here: http://www.enago.com/academy/immediacy-index-useful-for-journal-evaluation/

Many organizations rank journals in order of influence. Each has its own formula for creating its rankings, which are based on a mix of subjective features such as "perceived prestige" and somewhat more quantitative measures such as the number of citations a journal receives within a given time period (see "Impact Factors" at right).

Important note: Because journal rankings are based on citations to articles in already published journals, they always lag at least a year or two behind the current issues. Therefore, a journal ranking published in 2012 will most likely rank journals from 2010 or even earlier.  

SCImago Journal and Country Rankings (SJR) is a freely accessible web site that ranks more than 21,500 journals from the Scopus database. SCImago was developed by a group of researchers in Spain. You can sort journals by discipline or country of origin, and the results can be downloaded into an Excel document.

CiteScore: Another free site, developed by Elsevier, that ranks the publications indexed in Scopus. It uses a different set of metrics and different methodology from SCImago, which can lead to divergent results.

Eigenfactor.org is a freely accessible web site that offers two ways to rank journals: by "Eigenfactor" or by "Article Influence" (see "Impact Factors" at right). Eigenfactor ranks the journals in the Thomson-Reuters Journal Citation Reports collection, plus more than 100,000 other journals. You can sort by discipline and also see visualizations of the how the data change over time, etc.

Google Scholar has a "metrics" feature that offers a list of the top 100 journals in various disciplines by citation count. However,some of the entities it counts as "journals" are actually databases (e.g. RePEc and ArXiv), so it's possible that some journals' rankings are inflated by having their citations counted twice. You can see explanations of what goes into the Google Scholar rankings here.

Probably the most widely known rankings are the Journal Citation Reports (JCR) created by Thomson-Reuters (now Clarivate Analytics) to assess journals in Web of Science. The most up-to-date rankings are available only to subscribers, but below are links to fairly recent rankings in various disciplines. Also, if a journal has an Impact Factor you can often find it somewhere on the publisher's web site. 

JCR top-ranked Business Journals

JCR top-ranked Economics Journals 

JCR top-ranked Finance Journals

JCR top-ranked Nursing Journals

JCR top-ranked Health Policy and Services Journals

JCR top-ranked Education and Educational Research Journals

JCR top-ranked Environmental Studies

JCR top-ranked International Relations Journals

JCR top-ranked Political Science Journals

For an in-depth analysis of SCImago vs. JCR, see this 2010 article by Peter Jacso: Comparison of journal impact rankings in the SCImago journal & country rank and the journal citation reports databases. Online Information Review, 34(4), 642-657. doi: 10.1108/14684521011073034

SCImago Journal & Country Rank (SJR Indicator) is a citation tool and portal that includes the journals developed from the information contained in the database Scopusfor evaluating a journal’s impact factor. The last two years of citation activity are calculated and access to SJR indicator is free.  For a more in depth explanation of the metrics of this system click here: http://en.wikipedia.org/wiki/SCImago_Journal_Rank

To perform a journal ranking search using SJR, click here: http://www.scimagojr.com/journalsearch.php

Altmetrics was created as an alternative source to academic citation impact metrics, such as IF, h-index, g-index, etc.  Since 2010, Altmetrics looks at what people are saying about papers online which includes article views, downloads, or mentions in social media and news media.  For more in-depth information on Altmetrics click here: http://www.ala.org/acrl/publications/keeping_up_with/altmetrics

Impactstory.org  is another alternative source of impact metrics and it tracks how your research is read, cited, tweeted and bookmarked.  For more in-depth information on Impactstory.org click here:

https://impactstory.org/about

The phrase "impact factor" is trademarked by Clarivate Analytics, and is their term for the "measure of the frequency with which the 'average article' in a journal has been cited in a particular year or period."[1] More generally, we use "impact factor" to describe the relative prestige of a journal or a scholar within a field of study. The impact factor is an important component of a journal's ranking (see "Journal Rankings" at left).

As with journal rankings, impact factors are calculated by many different organizations, and each has its own algorithm. Some of the best known measures of impact are listed below.

Impact Factor: Used by Clarivate Analytics, assigns a numerical value to a journal based on the number of citations an "average article" in that journal receives over a set time period. A higher impact factor denotes a more prestigious journal. Only publications indexed in Web of Science receive Impact Factors, and the full annual report is available by subscription only. For a more detailed explanation, click here.

CiteScore: A free service from Elsevier, CiteScore operates in a similar fashion to the Impact Factor but uses different metrics. Because it includes reviews, editorials, and other items besides research articles in its calculations, it can lead to markedly different results from Impact Factor. Only publications indexed in Scopus receive CiteScores.

Eigenfactor: Developed by scholars at the University of Washington, the Eigenfactor is a variation of the Impact Factor in which some citations are weighted more heavily than others based on the rank of the journal they come from. Eigenfactor has been described as a measure of a journal's influence. For a more in-depth explanation, click here.

Article Influence: Developed by the Eigenfactor team, Article Influence uses the number and quality of citations to individual articles within a journal to determine the journal's ranking. Article Influence is related to and dependent on Eigenfactor. For a more in-depth explanation, click here.

H-index: Developed by Jorge Hirsch at UC San Diego, the h-index measures the impact of a particular scholarly author, rather than a journal, by a calculation that involves the number of articles that author has published and the number of times those articles have been cited. A high h-index indicates both that an author has both published widely and been cited widely. For a more in-depth explanation, click here.

PoP uses Google Scholar queries to obtain citation information, which is then analyzed and converted to a number of statistics.  Advantages of using Google Scholar over ISI or Scopus   1. It is free 2. It is easy to use 3. It is quick 4. It is comprehensive in its coverage.  PoPwas designed to calculate citation metrics and can assist with:

1. Deciding which journal to submit your work to.
2. Getting ideas of the types of journals that publish articles on the topic you are writing on.
3. Compare a set of journals in terms of their citation impact.
4. Perform a quick literature review to identify the most cited articles and/or scholars in a particular field.
5. Identify whether any research has been done in a particular area (useful for grant applications).
6. Doing bibliographic research on both authors and journals.
7. Find out who is citing you and where.

Impact Factor (IF)

The IF of an academic journal measures its importance by calculating the number of times its articles are cited. To understand how an IF is calculated, the calculation is based on a two-year or five-year period and involves dividing the number of times articles were cited by the number of articles that are citable. The concept IF was created by Eugene Garfield (founder of the Institute for Scientific Information). It is important to remember experts stress that there are limitations in using impact factors to evaluate a scholar's work. Examples of citation systems that use a calculation in order to evaluate the impact of a scholar or journal are: h- index;   g-index;    e-index;   hc-index;   hI-index;   hI,norm.  For a full discussion of each index click the link below.