How does a researcher gauge the impact of his/her research? How do administrators objectively evaluate the performance of a researcher?
While both questions are difficult to answer, below are numeric measures that can provide a rough snapshot of impact.
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A measurable indicator of an individual’s impact is the number of citations to articles and books they’ve written, as a crude measure of how much their work is being used to advance the research of others. This raw count of citations will vary depending on what the data source includes, and it’s hard to compare for researchers in different fields and at different career stages. Citation counts can be found in:
- Web of Knowledge: This proprietary database, also called Web of Science or Science Citation Index, is the longest-running source of citations. For tips on getting citation counts, such as removing self-citations, see Citation Research LibGuide: Web of Science or this section of a Web of Science workshop video.
- Scopus: An abstract and citation database with a single search platform searching content from ScienceDirect, Scopus, SciTopics, and relevant Web content.
- Google Scholar: This free database, huge but still in beta-testing, counts citations from both scholarly and non-scholarly sources. For tips on finding citations in it, see Citation Research LibGuide: Google Scholar.
- Some subject-specific databases now include citation counts, including SciFinder Scholar for chemistry and MathSciNet for mathematics.
Article Download Count
Some web platforms provide download counts for individual hosted publications. This activity measure indicates interest at that level, but because of non-uniform criteria, there is no standard way to aggregate counts from different systems. Examples of platforms that provide download counts include the University’s Digital Conservancy (via an item's Stats Display), and Public Library of Science (in an article's Metrics tab).
This measure aims at productivity as well as impact by counting how many of an author’s papers have been cited many times; to have an h-index of 5, five of a scholar’s publications must have been cited by others at least five times each. While more sophisticated than plain citation counts, the h-index shares the limitations of incomparability across fields and across career stages. An individual’s h-index may be found in
- Web of Knowledge by generating a Citation Report for a specified author, as shown in this Web of Knowledge tutorial.
- Scopus by searching for an authors name or clicking on a linked author field, as described in this tip sheet.
- Google Scholar, after installing a tool such as the Google Scholar Universal Gadget, Publish or Perish software, or the Scholarometer add-on for Firefox or Chrome browsers.
Various alternative metrics have been invented and written about; for example, the g-index modifies the h-index by giving greater weight to highly-cited articles. In addition to citation counts, additional factors such as page views, pdf downloads, tweets, blog mentions, and wikipedia citations weigh into your altmetric impact. Here are some popular tools to track these alternative measures:
For more information, see this primer on AltMetrics by the American Library Association (2013).
Science Metrics, a Nature News special issue (6/16/10) discussing various individual productivity measures.
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