The impact factor of a journal is a scientometric index that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as indexed by Clarivates Web of Science. It is used to measure the importance or rank of a journal by calculating the times its articles are cited. The higher the impact factor, the more highly ranked the journal.
- The impact factor is calculated by dividing the number of times articles were cited by the number of articles that are citable.
- It is a useful tool for comparing journals in the same subject category.
- The best journals in a specialty are often those with a high impact factor, as they are more difficult to have an article accepted.
- However, the impact factor is not a perfect tool for measuring the quality of articles, and its use as a measure of quality has limitations.
- Not all journals are tracked in the Journal Citation Reports (JCR) database and, as a result, do not have impact factors.
- New journals must wait until they have a record of citations before being considered for inclusion in the JCR database.
