What are metrics?
How does the scientific community measure how "good" or "great" a journal is? How do you determine the "impact" of an author's work? Should it be purely on the number of citations? Or is it a matter of the "quality" of the research? But then again, how do you measure "quality"?
These questions caused people to create methods on how to calculate the impact or "good-ness" of an article, journal, or author. These calculations and statistical methods are called metrics. Metrics are debated over, and over, and over. Most popular metrics include: number of citations, impact factor, and h-index. There are hundreds of other metrics available, some better defined than others. See the link below for more information about other available metrics.
- Impact Metrics and Scholarly AttributionThis LibGuide provides an overview of other metric methods available (other than impact factor and h-index) that are being developed.
Attribution and credit for the linked guide is given to UCLA Science and Engineering Library and UC Irvine Libraries. - Spreading the Word: Publishing Your Research & Extending Your ImpactThis guide has information to help you identify major journals in your field and understand how a journal or article's impact is measured. Information on open access is also included.
Impact Factor
One metric used is impact factor. According to Journal Citation Reports (JCR), the impact factor is a ratio focusing on original research.
Impact factor = # of citations to all items published in the past two years (divided by)
# of articles and reviews published over those past two years.
For example, if a journal has an impact factor of 2.5, this means in the indexed year each article published was cited on average 2.5 times in the previous two years.
Impact factor is used for journals only.
- InCites Journal Citation Reports This link opens in a new windowAllows evaluation and comparison of scholarly journals.
h-index
Journals have impact factor, authors have the h-index. h-index is somewhat complex calculation taking into account the total number of articles published by an author and the number of citations per article.
An author's h-index, or h, is equal to the number of total articles published, as long as every article has at least h number of citations.
h-index is used for authors only.
- Google Scholar This link opens in a new windowFiltered Google Search finding scholarly journal articles, books, citations, and case law.
- Web of Science This link opens in a new windowInterdisciplinary collection of journal articles, conference proceedings, and books. Collection of seven online database: Conference Proceedings Citation Index, Science Citation Index, Social Sciences Citation Index, Arts & Humanities Citation Index, Index Chemicus, Current Chemical Reactions, and Book Citation Index. Coverage is 1900-present.