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Research Impact Measurement: FAQs


1. What are citation metrics?
Citations are an indicator of an article’s worldwide influence and the means by which researchers acknowledge other researchers. Citation metrics are a quantitative way of measuring and ranking research impact based on citations counts. They measure productivity, influence, efficiency, relative impact and specialization and can be applied to an individual, group, institution, subject area or geographic region.

Examples of citation metrics:

  • Total number of papers: the number of papers published by a research within a stated timeframe.
  • Total number of citations: the sum of the citation counts across all papers.
  • Hirsch's h-index: “a researcher has index h if h of his/her x papers have at least h citations each”

2. What does the h-index measure? Why are researchers so interested in it?
The h-index is a measure of an author's impact based on the citation rates of their articles published. The h-index is calculated by establishing how many publications are attributable to an author that contain at least that same number of citations e.g. if an author has a h-index of 8, they have 8 publications that have been cited at least 8 times.

3. How can I find my h-index?
The h-index can be generated in both the Web of Science and Scopus databases. The h-index may not be the same in both databases because different citation databases cover different publication sources as well as date ranges. Citation data obtained from a particular database is derived from journal titles that are indexed by that particular database.  

4. Why use citation metrics?
Citation metrics can be used as an indication of the importance and impact of an individual researcher or that of a research group, department or university, and their value to the wider research community. Applications for funding, research positions or promotion may require citation metric data. University rankings also take citation metrics into account.

5. Is citation metric data reliable?
Citation metrics have their limitations. Self-citations, differences in metrics depending on the data source, multi-author publications giving equal credit to all authors and certain metrics favouring experienced researchers over early career researchers are just some factors that affect the “reliability” of citation metrics.

6. Which databases can I use to search for citations and generate citation metrics?
The main resources for citation searching include Web of Science, Scopus and Google Scholar.

7. How can I find out how often my publications have been cited?
A number of databases include journal article citation information:

You can conduct a search for a published article in any of these databases and you will be able to view a list of all the articles in the database that have cited that published article. This is highly dependent on the journal coverage of that database.

8. Can I be notified each time my publication is cited?
You can set up a citation alert in Web of Science or Scopus so that you receive a notification each time your publication is cited by other sources that are added to the database.

9. What is a Journal Impact Factor?
The Journal Impact Factor (JIF) uses citation data to assess and track the impact of a journal in relation to other journals. The impact factor is recalculated each year: the number of citations received in that year is divided by the total number of articles published in the two previous years.

10. How can I find the impact factor for a particular journal?
You can find out the Journal Impact Factor for a particular journal using Journal Citation Reports (JCR).

11. How can I find out which journals in my field have the highest impact factor?
You can find out the Journal Impact Factors for journals in a particular field using Journal Citation Reports (JCR).

12. How reliable are Journal Impact Factors?
The Journal Impact Factor (JIF) has been criticised for not accurately reflecting the value of the work published in journals. As the measure is based on the number of citation counts received by articles in a journal it cannot be used to compare journals across disciplines and is biased towards journals that contain more heavily cited publication types, such as review articles or methods papers. It is also open to editorial manipulations. The San Francisco Declaration on Research Assessment (DORA) makes recommendations for improving the way in which the quality of research output is evaluated, including the need to eliminate the use of journal-based metrics, such as the Journal Impact Factor.

13. Are there alternatives to the Journal Impact Factor?
Alternative metrics available to measure the impact of a journal include:

  • Eigenfactor score - This is similar to the Journal Impact Factor, but citations are weighted, with citations from highly ranked journals making a greater impact on the final Eigenfactor score than citations from journals with lower rankings. The Eigenfactor score is based on data from the Web of Science database.
  • CiteScore - similar to Journal Impact Factor, this looks at publications indexed in Scopus and provides the average number of citations that are received in the respective journals.
  • SCImago Journal Rank (SJR) - The SJR is very similar to the Eigenfactor score and also gives more weight to highly ranked journals. The SJR is based on data from the Scopus database.
  • SNIP (Source Normalized Impact Per Paper) - SNIP weights citations according to subject field, with higher value given to a citation if it is from a field where articles tend to be cited less frequently. SNIP is based on the Scopus database.

14. What are Altmetrics?
Altmetrics is an emerging field which aims to measure the impact of published research on the social web. This type of measure can supplement the information gained from traditional Citation metrics. Altmetrics can also be used to gauge the impact of publications that would not be included in traditional citation metrics, for example data sets, software, or presentations.

Altmetrics are based on data such as:

  • Blog cites
  • Twitter cites
  • Mendeley records
  • Online repository records
  • Article views and/or downloads
  • News or media mentions etc

Besides demonstrating impact, Altmetrics can be used to find collaborators, or to provide evidence of engagement with the content of a publication.

More information about Altmetrics can be found on our Altmetrics page.

15. What effect does open access publishing have on citation metrics?
Various studies have been carried out to determine whether open access publishing has an effect on the number of downloads or citations a piece of work receives. The results vary across disciplines. SPARC maintains a list of studies which addresses this question.

16. I would like to know more about predatory journals, publishers or conferences. Where can I find out more?
You can refer to our libguide on predatory publishing for more information about predatory publishing and predatory journals. Resources like Think Check Submit or Think Check Attend are also useful as they provide a checklist for authors to refer to when they come across any predatory publisher or organisers. You can also contact us for more information and advice on the topic.

Contact Us!

The Research Impact Measurement team at NUS Libraries provides consultations on matters related to citation metrics, using databases, journal metrics, author profiles, NUS Elements, predatory publishing and provides advice on citation metrics for Annual Reviews, Promotion & Tenure or benchmarking.

Do feel free to contact us if you have any questions: