Impact data is used to evaluate the relative importance of a journal, an individual publication, or a researcher to a field of study. Tools used to measure impact, include journal impact factors, citations to publications, and the h-index of researchers.
Limitations in the use of bibliographic metrics to measure researcher impact
- The number of times a paper is cited is not necessarily a measure of quality
- Measurement tools may favor specific types of scholarly communication and / or do not include different types of publications, including textbooks, reference books, etc.
- Certain disciplines have low numbers of journals and/or low journal usage
- Review articles are cited more often and change results
- Self-citing skews results​
- Working in a small field, publishing in a language other than English, or publishing mainly in books, generates fewer citations
