Researchers and academic staff are often required to demonstrate the impact of their research when applying for research grants, promotions and new positions. 

Citation metrics are used to measure the impact of scholarly works within academia. 

Standard citation metrics include citation counts and the h-index. These measures assume that significant scholarly works will have higher citation counts.

Citation count refers to the number of times a scholarly work is cited. The h-index or Hirsch index measures a researcher's productivity and citation impact. A researcher has an h-index of h if his/her papers are cited at least h-times. 

Citation databases

Citation databases are used to measure individual and institutional citation performance. Several citation databases should be used to calculate citation impact as journal indexing and citation counts vary in each database. 

The most comprehensive sources of citation data are the Web of Science, Scopus and Google Scholar databases.

Citation counts are also available from subject-specific databases. A list of citation databases is available here.