Citation Research and Impact Metrics

About the Relative Citation Ration (RCR)

iCite provides analysis for articles appearing in PubMed. Citation data are drawn from several data sources: PubMed Central, European PubMed Central, CrossRef, and Web of Science. iCite includes the Relative Citation Ratio (RCR) for an article that is a citation-based metric developed by NIH.

Important Points:

• The RCR is calculated as the citations per year for an article, compared to the expected number of citations per year received by NIH-funded papers in the same field and year. The "expected number of citations" is both the unique and controversial aspect of this metric. The research field is defined as all the references in the articles that cite the article under interest. An "expected citation rate" is then determined using the citation counts for the items in the field. An article with an RCR of 1.0 has received the same number of citations per year as the median NIH-funded paper in the same field; an article with an RCR of 2.0 has received twice as many citations per year. For more details on RCR calculation, see the references below.
• The article must be covered in PubMed to be analyzed by iCite.
• To analyze a set of citations, the set must be no larger than 1,000 items.
• Coverage starts with articles published in 1995.
• Determination of the "expected citation rate" is controversial.​

Uses:

• Most useful in academic units with large percentage of NIH funding and/or publications appearing in health sciences journals.

To Get the RCR:

• Enter the title of the article in the "Search PubMed" box
  
• Click on the blue "Process" button at the bottom of the screen
• The results page will display
• The weighted RCR is near the top and far right of the table.
  

For details about the information on the results page (and more), click on the Help link in the upper right corner of the screen.

CiteScore is a relatively new (December 2016) product from Elsevier, using citation data from the Scopus database to rank journals. In this metric you compare an article's citation count to what CiteScore says would be expected of the average article in this journal.

Important Points:

• The CiteScore goes back to 2011 so only relatively recent articles can be assessed by this metric.
• The article must be in the Scopus database.
• The article must have been published in the three years immediately preceding the journal's CiteScore. For example, if you are using the journal's CiteScore from 2015, the article must have been published in 2012, 2013 or 2014.
• The CiteScore includes traditionally non-cited front matter in its calculations, therefore, journals with substantial front matter have lower scores when compared with their JIF (which does not include front matter in its calculation).
• Arguably, this is an "apples to oranges" comparison; you are comparing article performance (actual citation count) to journal performance (average citation count), so use with caution.

How to get the comparison between the article and the journal's CiteScore.

In this example, we want to compare an article's performance in 2015 to its journal's 2015 CiteScore; because the 2015 CiteScore is derived from the citation counts of articles from 2012 -2014, to keep the comparison as "apples to apples", the article we pick must have been published from 2012 through 2014. (If you want to compare an older article, use a CiteScore from a year that is no more than 3 years past the article's publication date. Because CiteScores go back only to 2011, articles published prior to 2008 cannot be assessed by this method.)

Example:
Lascaris E., Hemmati M., Buldyrev S.V., Stanley H.E., and Angell C.A. Search for a liquid-liquid critical point in model of silica. Journal of Chemical Physics, 140 (22), article number 224502, 2014.

1. Go to CiteScore
2. Change the search box dropdown from "Subject Area" to "Title"
3. Enter the title of the journal: "Journal of Chemical Physics" and click on the blue "Find sources" button
4. In the top right of the search results, click on the date dropdown and select 2015
5. From the results we can see that the CiteScore for the "Journal of Chemical Physics" in 2015 was 5.2, indicating that the average article published in that journal from 2012-2014 was cited just a little over 5 in publications that came out in 2015.
    
6. Now go to the Scopus database to see how many times the article in question was cited by 2015 publications.
7. Enter the title of the article in the search box; we recommend enclosing the title in quotes to make the search more efficient.  If the title is long, consider entering just the first 5-7 words.
8. On the results list, look in the far-right hand column to see how many times this article has been cited since it was published.  Click on that number to bring up the list of those citing publications. 
9. Because we are comparing this article's performance with the journal's 2015 performance, we must limit our list of citing articles to just those that were published in 2015.  To do that, go to the left-hand column and under "Year" click on 2015 and then the "Limit To" button near the top of the column. The list of citing articles is reduced to 5. 
   
   
    
10. So the article under assessment was cited more than twice the amount expected (5 vs. 1.98) of the average article in this journal for 2015.  
11. Now is the time for adding the quality assessment.  Is the article being cited for positive or negative reasons?  Who wrote the articles that are citing the original article?  Are the citing authors well-respected members of the field?  Do you give the same weight to self-citations as you do to external citations?  

The Field Citation Ratio is calculated for all publications in Dimensions which are at least 2 years old and were published in 2000 or later. It is calculated by dividing the number of citations a paper has received by the average number received by documents published in the same year and in the same Fields of Research (FoR) category. Values are centered around 1.0 so that a publication with an FCR of 1.0 has received exactly the same number of citations as the average, while a paper with an FCR of 2.0 has received twice as many citations as the average for the Fields of Research code(s).

In order to calculate an FCR score for an article, a minimum number of 500 articles need to be categorized in the applicable FoR category for the year in which the article was published. If an article is categorized in more than one FoR code, then only those codes which meet the threshold of 500 labeled articles in that year will be used to calculate the FCR score.

Compared to the Relative Citation Ratio (RCR), the FCR uses a more tangible definition of a field, i.e. you can get a list of all articles in a specific FoR code - the same is not possible for RCR where the a field is relative to the publication in question.

From "What is the FCR? How is it Calculated?"

An article's citation count may be compared to where it falls on the journal's citation distribution curve (CDC). Unfortunately, most journals do not provide a citation distribution curve but a simple citation distribution "list" can be determined easily through the Scopus database. When comparing an article's citation count to the citation distribution of a journal, we recommend using articles from the same year; so if you are assessing a 2014 article, find the citation distribution for articles published in that journal for 2014.

Because this metric is not using an "average" as the benchmark (as you get with CiteScore or the Journal Impact Factor) there is less chance of an outliers' effect artificially inflating the benchmark.

Determining a Journal's Citation Distribution via Scopus:

1. Go to Scopus
2. Find the article and get its citation count (searching by the article's title is usually the most efficient.)
3. Go back to the database's main search page and do a search for the journal title and change the search field to "Source Title"
4. On the results list, go to the left-hand column and look under "Source Title" to see what Journal Titles the search has retrieved. If it has retrieved other titles in addition to the title you want, click on the desired title and then click "Limit To"
5. Once the results list refreshes, return to the left-hand column under "Year" and select the year of the article you are assessing. Again, click "Limit To"
6. Once the results list refreshes, again, return to the left-hand column this time under "Document Type" and select "Article" and "Review".  Again, click "Limit To"
7. Once the results list refreshes, go to the header bar above the list and set the list sort option to "Cited By"
8. You now have a list ordered by citation count of all the articles in the same year as your article of interest. By checking where the article falls within the list tells you whether the article performed better, worse or on average with the articles in the same journal for that same year. A good way to quantify this placement is to determine what percentile the article achieved (ex., its citation count is higher than X% of the articles published in that journal during that year).

If you are comfortable with creating graphs within an Excel file, you may also see the actual citation distribution curve and plot your article's citation count on the curve. See this article for how to do it using data from the Web of Science: