Confusion between citation databases: how are they related? I have seen in some faculties that I have been visiting that they give more importance to some citation databases than to others. About this issue, I have some confusions. I prefer to open only one global question here that cutting it up into smaller chunks because I believe the things I will expose are related:


What is the importance that some journals are indexed in Scopus and some in Web of Science or Thomson Reuters? Does Scopus have a better reputation? I ask this because I saw one faculty that strive to put their publications only on journals and conferences indexed by Scopus.
Is there any relationship between Scimago and Web of Science?
I found in the following link:
http://www.thomsonscientific.com/cgi-bin/jrnlst/jlresults.cgi
that a journal in which a colleague has gotten his article published that appears on this list, does it mean that journal is indexed by the Web of Science? Even though I have seen in the webpage of that journal that it does not mention Web of Science perse.


Any clarification of these citation databases would be a huge help to me. The field that I am working on is Computer Science.
Web of Science is probably marginally more selective; Scopus is a little broader (I routinely get higher numbers of hits in Scopus for comparable searches). My understanding is that Scopus has also made a deliberate attempt to increase its coverage of conference proceedings, which would mean more significant coverage in those disciplines which are very conference-oriented - ie engineering and computer science - but I'm not a CS specialist so please don't take that as gospel. "Only on Scopus" may be a deliberate nod to this, or it may simply be that that institution subscribes to Scopus and not WoS!
No, they are not connected. Web of Science is based on the "Science Citation Index", but this is not connected to SCImago.
Thompson Reuters were the owners of the Web of Science product. (They sold it recently and it's now owned by Clarivate Analytics, an independent firm not part of any of the major publishers). Web of Science contains a number of distinct databases; the link you give there is a 404, but it looks like it would be some subset of this list. It probably indicates that the journal will be found in at least some part of the Web of Science product, though I believe not all institutions subscribe to all parts of the service. (You can always plug the journal into Web of Science and see what comes up...)