Measuring Research Impact: Citation analysis tools

Metrics Methods and Evaluation

Citation databases and tools

The three best known citation analysis databases are Web of Science (WoS), Scopus and Google Scholar (GS). The citation data will relate only to articles indexed within the database. Using citation information from multiple databases and comparing the results can offer a better perspective of impact within a field.

WoS and Scopus mainly cover international journals, whereas the social sciences and the humanities also publish in chapters, monographs and national journals. Google Scholar iIndexes all document types – journals, conference proceedings, books, theses, preprints etc. It has better coverage of non-english material than WoS and Scopus.

Distribution of journals by field in Wos and Scopus

Source: Mongeon, P. & Paul-Hus, A. The journal coverage of bibliometric databases: A comparison of Scopus and Web of Science 10.2.2015
ASIS&T 2014 Annual Meeting: Metrics 2014 Workshop

Web of Science by Thomson Reuters
Web of Science is a citation database of select high profile journals and other scientific publications.
Subject coverage: predominantly sciences, including agricultural, biological, & environmental sciences, engineering, technology, applied science, medical & life sciences, and physical & chemical sciences. Social sciences, arts and humanities to a lesser degree.
Content overview
Components available in the University of Helsinki network:
Web of Science Core Collection (1945-), Current Contents Connect (1998-), Derwent Innovations Index (1963-), KCI-Korean Journal Database (1980-), MEDLINE (1950-), SciELO Citation Index (1997-)
Web of Science Training videos

Web of Science Core Collection
Content overview
Components available in the University of Helsinki network:
Citation indexes in science (1945-), social sciences (1956-), arts & humanities (1975-), conference proceedings (1990-), books (2005-). Chemical indexes: Current Chemical Reactions (1985-) and Index Chemicus (1993-).
Quick Reference Guide

Scopus by Elsevier
A citation database of peer-reviewed literature: scientific journals, books and conference proceedings.
Citation data primarily from 1996 onwards.
There is overlap in journal titles indexed between Scopus and WoS, but Scopus includes over 8000 unique journal titles as compared to WoS - WoS over 900 compared to Scopus. (
Subject coverage: predominantly sciences, including physical sciences, health sciences and life sciences. Slightly higher proportion of social sciences journals, when compared to Web of Science.
Content Overview
Scopus Content Coverage Guide
Scopus Tutorials

Google Scholar by Google
Consists of scholarly articles including journal papers, conference papers, technical reports, theses, pre-prints, post-prints and other publications on the Web. Google Scholar's strength is the broad scope of content for both types of publications and disciplines. There is also a better international and multi-lingual coverage than in Wos or Scopus. However, only a small portion of all published scholarly literature is included.  Because there is no complete list of sources indexed on Google Scholar, there is no way to know how comprehensive your searches are or how much information is available. GS contains a lot of citations that are not scientific ones. That is why the sum of citations is usually  much greater than the sum  in WoS and/or Scopus. There is no information available about the time span and coverage of GS.
May be useful for fields not sufficiently covered by WoS and Scopus.
Google Scholar Content Coverage
Google Scholar Quick Guide / Oulu University Library
Tools that draw data from Google Scholar to analyse citations:
Scholarometer is a social tool to facilitate citation analysis and help evaluate the impact of an author's publications. It works as a browser extension for Google Chrome or Mozilla Firefox.
Publish or Perish is a software program that must be installed on your computer. It offers a wide range of statistics, with several types of indexes provided.

Search Web of Science

Search Web of Science Core Collection™

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Citation analysis

Citation analysis examines the linkages between citing articles. It is the study of the impact of a publication, an author or an institution based on the number of times works and/or authors have been cited by others.
Read more:
Citation analysis and databases containing citation information / Oulu University Library

Subject area specific


  • Citations of a publication reveal the positive or negative attention it has received rather than indicate its quality
  • Citations are a researcher's subjective choice, which can be affected by many factors, e.g.age, language or easy availability of a publication
  • Different citations in a paper are usually unequally important - the cited reference is either marginally or highly related to the article citing it
  • Different citations usually come from papers with different influence and quality
  • Document age and discipline influence the number of citations it has, or is likely to receive.

The citation data will relate only to articles indexed within the database. Variation may occur because the databases:

  • Index different publication sources
  • Cover different date ranges
  • Include poor-quality data (duplicate records, misspelt citations etc)