Journal Self-Citation Trends In 1975-2017 And The Effect On Journal Impact And Article Citations

This paper investigates journal self-citation trends between 1975 and 2017. The research sought to answer whether articles that include journal self-citations are more highly cited, if they affect the journal impact factor, and whether such articles are more relevant to their journals' content than others. We analysed approximately 24,000 active journals indexed in the Web of Science from 1975 to 2018 and found that, over time, whilst overall citations have increased dramatically, the percentage of journal self-citations has reduced. Although self-citations to recently published articles has increased since 2004, self-citations also seem to have a decreasing effect on impact factor. High-impact journals self-cite recent publications more than lower-impact journals but also cite recently published content more frequently than lower-impact journals. There is a positive citation effect on articles that include journal self-citations, and these appear more related to the current content of that journal based on the relatedness of references. Journal self-citation can therefore be seen as a useful indicator to determine whether an article is a good fit for a journal and of interest to its readers. It may also contribute to higher visibility and impact of an article.