Research impact can be defined as the significance of research within and outside of the academic world. Individual researchers as well as institutes are expected to show their research impact as part of various important processes. For managers, these can for example be SEP Evaluation and recruitment and promotion. For researchers, examples are applications for research funding and tenure track selection at intake. The University Library offers support for researchers and management on determining, increasing and maintaining research impact.
Academic impact can be defined as the significance of research for stakeholders within the academic world. To measure this significance, various quantitative indicators – often referred to as bibliometrics – are used. Below the most dominant quantitative indicators are explained, based on the definitions in the metrics-toolkit. For appropriate use, data sources and more please click on the ‘more info’ links.
- H-index: author-level metric calculated from the count of citations to an author’s set of publications. A researcher has index h if h of the researcher’s Np papers have at least h citations each and the other (Np – h) papers have fewer than ≤ h citations each. For example, an author with an h-index of 6 has at least six publications that have each been cited at least six times each. (more info)
- Citations: the number of times that a research output has appeared in the reference list of articles and books. Can apply to scholarly outputs such as journal articles, reviews, and preprints (more info), books and book chapters (more info) and data sets (more info).
- Field Normalized Citation Impact: the ratio between the actual citations received by a publication and the average number of citations received by all other similar publications. The latter is referred to as the expected number of citations. Similar publications are ones in the same subject category, of the same type, and of the same age. Applies to journal articles, but also book chapters and conference proceedings that are sufficiently covered by abstract and citation databases. (more info)
- Citation percentiles and Highly Cited labels: the position of a paper or group of papers with respect to other papers in a given discipline, country, and/or time period, based on the number of citations they have received. Expressed as a percentile or awarded a “Highly Cited” honor based upon percentile rankings. (more info)
- Journal Impact Factor: a measure of the frequency with which the “average article” in a journal has been cited in a particular year or period. Journals selected for indexing in Science Citation Index Expanded and/or Social Sciences Citation Index are eligible to have a Journal Impact Factor. (more info)
Societal impact can be defined as the significance of research for stakeholders outside the academic world, such as industries, policy makers and citizens. To measure this significance, various quantitative indicators – often referred to as alternative metrics or altmetrics – are used. Below the most dominant quantitative indicators are explained, based on the definitions in the metrics-toolkit. For appropriate use, data sources and more please click on the ‘more info’ links.
- Altmetric Attention Score: an automatically calculated, weighted count of all of the attention a research output has received online, in sources – such as social media, policies, patents and news items - tracked by Altmetric. Can apply to journal articles, books, and any research output deposited to a repository that the Altmetric tracks. (more info) Explore your online attention directly via our subscription to Altmetric Explorer.
- Mendeley readers: the number of Mendeley users that have added a particular document to a Mendeley library. Can apply to primarily journal articles, but also other types of research outputs, such as web pages, books and conference papers, which users add to their Mendeley reference libraries. (more info)
- Downloads: an event triggered by a user clicking on the download button, in contrast to simply viewing a web page. Can apply to journal articles or other serial publications (more info), books and book chapters (more info) and software (more info).