SCImago Journal Rank: Difference between revisions

If scientific impact is considered related to the number of endorsements, in the form of citations, a journal receives, then prestige can be understood as a combination of the number of endorsements and the prestige or importance of the journals issuing them. The SJR indicator assigns different values to citations depending on the importance of the journals where they come from. This way, citations coming from highly important journals will be more valuable and hence will provide more prestige to the journals receiving them. The calculation of the ''SJR indicator'' is very similar to the [[Eigenfactor]] score, with the former being based on the [[Scopus]] database and the former on the ISI [[Web of Science]] database<ref>{{cite web | title=SCImago Journal & Country Rank (SJR) as an alternative to Thomson Reuters's Impact Factor and EigenFactor | url=http://www.scimagojr.com/news.php?id=41 | date=21 Aug 2008 | accessdate=20 September 2012}}</ref>.

The SJR indicator computation is carried out using an iterative [[algorithm]] that distributes prestige values among the journals until a steady-state solution is reached. The SJR algorithm begins by setting an identical amount of prestige to each journal, then using an iterative procedure, this prestige is redistributed in a process where journals transfer their achieved prestige to each other through citations. The process ends up when the difference between journal prestige values in consecutive iterations do not reach a minimum threshold value any more. The process is developed in two phases, (a) the computation of ''Prestige SJR'' (''PSJR'') for each journal: a size-dependent measure that reflects the whole journal prestige, and (b) the normalization of this measure to achieve a size-independent measure of prestige, the ''SJR indicator''.