The Journal Impact Factor is the average number of citations received in the last year to articles published in the previous two years. It is measured each year by the Web of Science Group and reported in the Journal Citation Reports (JCR). The JCR analysis released in 2020 is based on citations in 2019 to articles published in 2017 and 2018.
The Journal Impact Factor is often misused as an indicator of an article’s or author’s impact and its use is problematic, including to determine the quality of a journal. High citation rates can have a disproportionate effect on the mean number of citations per paper. For this reason, we are committed to building alternative and comprehensive impact metrics for articles, authors and journals and are a signatory to DORA, supporting the responsible use of journal impact metrics.