The first thing is not to confuse the 2 metrics as Impact factors. Thomson Reuters have the Impact Factor (IF), measured by citations within it's JCR database. SCImago is an alternative measure based on a different citation universe provided by Scopus. SCImago uses a weighted citation score meaning that citations from a prestigious journal are scored more highly than those from a title that has a smaller citation network. The IF on the other hand uses absolute counts (a citation = a citation).

Universities may put different stock in each of these metrics but the 2 are largely incomparible. they measure 2 distinctly different things.

We run the danger of entering into a marketing game where institutions pick the metrics in which their research scores most highly.

The first thing is not to confuse the 2 metrics as Impact factors. Thomson Reuters have the Impact Factor (IF), measured by citations within it's JCR database. SCImago is an alternative measure based on a different citation universe provided by Scopus. SCImago uses a weighted citation score meaning that citations from a prestigious journal are scored more highly than those from a title that has a smaller citation network. The IF on the other hand uses absolute counts (a citation = a citation).

Universities may put different stock in each of these metrics but the 2 are largely incomparible. they measure 2 distinctly different things.

We run the danger of entering into a marketing game where institutions pick the metrics in which their research scores most highly.

It means if a journal has SCImago IF can be considered as good research journal. It is not comparable but have some value in research.

Thanks Juan, maybe I should clarify this a bit more:

SCImago offer different metrics as suggested dutifully by Juan but I don't think one should compare the actual SCImago calculation (I am talking about the SCImago calc not the H-index or cites per doc) with the impact factor and here are some of my reasons:

SCImago uses a 3 year citation count window where as the IF uses a 2 year. SCImago counts self citations up to 33% where as the IF counts all.

Database variances abound, these are not comparable calculations even if journals are similarly ranked using either scoring system. What SCImago and Eigenfactor aim to do is allow the comparison of journals across disciplines through weighted citation counting. Unlike the IF which is subject area dependent (although that in itself is questionable). One should never compare an IF score with a SCImago score.

Going back to the orginal question: yes, they are considered to be alternative metrics to each other.

SCImago was introduced by those who felt ISI IF was good only for citation counts and did not reflect the journal prestige or impact. That is why, it was also suggested may be we should use both IF and SJR to measure the rank of a journal. However, SCimago did not get as much acceptance as was received by IF. Then came Google Scholar Metrics (GSM)--h-index, which calculates both the author impact and journal impact and it seems to be be getting more acceptance among scientists with some modification. Now we are getting some variations of h-index, such as h1, hc. hi, hm, and other. So, the search for a better metric continues.

In all these comparisons, where does the RG impact factor stand?

Its really pathetic and shameful that i was trying to find some of the best journal in big data to submit my research work....for the last few hours ....i am trying to find out the journal impact factors and couldn't find any convincing answers......

There are tens of articles on pros and cons of impact factor in general. If you like to be more specific, you may find relevant papers on individual metrics, including JIF, SJR,,GS. If you provide us wit a little more detail about your question,, we maybe able to help you. .. .. 

SCImago uses Scopus as a source database, which is more comprehensive than WoS. Google Scholar is the largest of the three citation databases. Between JIF and SCImago (Scopus), JIF is more credible. Publishers are now printing JIF scores  as indicators of the quality of their journals. .JIF (WoS) has  has been in use for over 50 years and is highly used by scientists and researchers to measure the quality research .  It is also accepted as the standard metric or tool for journals ranking.  

Thank You Sir. I think JCR IF is more reliable in comparison to SCImago as when I told about the SCImago, everybody either they do not know about SCImago or they believe in only JCR (Thomson Reuters). Many Journals show their IF even they run only 1st or 2nd volumes. They are creating confusion and most of them are paid Journals.

In Polish science-metric system leads by the Ministry os Science and Higer Education only JCR IF is accepted. It is just a ministerial decision that only one system its used to measure the quality of universities.

I am late to this conversation, but just to point out, although the methods are indeed different these metrics are highly correlated. The provided link suggests about +.8, and the document also links to other studies of the extent to which these metrics agree with one another.

http://arxiv.org/pdf/1303.5870v1.pdf

All thte hreee hhree

All impact measures have limitations, and none are metrics in the mathematical sense.

SJR is limited to the Scopus database and JCR IF to the SCIE and SSCI databases. That is venues outside of these aren't indexed and citations from elsewhere aren't counted. SCImago does count certain conferences, but where the title it uses includes a number (3rd XXX 2012) it counts this as a separate publication and does not aggregate over years. SJR is weighted by 'prestige' in a regressive way similar to Google Page Rank, it reflects popularity and breadth of the topics covered by repeatedly upweighting the prestige journals and recalculating the weighted average citations (for articles published in the previous three years, or at the named single year event from the last three years) till a steady state is reached. It thus biases towards larger, older and more general venues and against smaller more specialized venues. The assumption is that a venue prestige/weighting is stable, and thus if SJR is provided for three separate events in the one conference series, the SJRs should be added to be comparable with indexed journals or series.

Google Scholar has the widest scope, but the venues for which it provides an h5-index are limited (h-index for last 5 years in their database). SCImago also provide h-index information (h-index for full period in their database, but often based on a single year  event rather than a full conference series). h-index is designed to measure the impact of authors, not journals and conferences, and represents the maximum number h of publications with at least h citations, and is thus limited by the number of publications (ever, or in the one year for individually indexed conference events) - it thus biases against smaller more specialized venues very directly.

SCImago SJR is freely available here:

http://www.scimagojr.com/journalrank.php?category=0&area=1700&year=2013&country=&order=sjr&min=0&min_type=cd&page=36

Google's h5-index is freely available here:

https://scholar.google.com/citations?hl=en&view_op=search_venues&vq=learning

There reverse approach to upweighting for prestige and volume, is normalization by number of publications, and I thus prefer a measure such as SNIP. Scopus (Browse Sources) also shows the unormalized IPP (Impact per Publication) and normalized SNIP (Source Normalized Impact Per Paper).

In the new project of evaluation of scientifical journals in Poland (May 2015)b SCImago should be used instead of ERIH list. For Art&Humanities olny, of course

why we must control to scopus and are another standar index

I do agree with Elman Shahverdiev. Actually, RG did just that, up to last year if I remember well. Maybe we users should try to ask RG to revert back to the previous method of calculating the impact of researchers on RG.

what is the Impact Factor of Global NEST by JCR?

I do not care about whatever impact factors. If someone likes it, let him enjoy.  But really new ideas reach the audience very slowly, such paper will not get attention for a long time. Even more - journals will not publish such papers. So, the impact factor is a POLITICAL factor - shows only the clan (and mafia) structure of science.

Thank you for a very good, clear and very documented clarification of these two databases value impact factor colleagues David Martin Ward Powers and Paul Trevorrow, that we will be very useful as an excellent information!

SCImago Journal Rank (SJR indicator) is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from. The SJR indicator is a variant of the eigenvector centrality measure used in network theory. Such measures establish the importance of a node in a network based on the principle that connections to high-scoring nodes contribute more to the score of the node. The SJR indicator, which is inspired by the PageRank algorithm, has been developed to be used in extremely large and heterogeneous journal citation networks. It is a size-independent indicator and its values order journals by their "average prestige per article" and can be used for journal comparisons in science evaluation processes.

The SJR indicator is a free journal metric which uses an algorithm similar to PageRank and provides an alternative to the impact factor (IF).[1][2] Average citations per document in a 2-year period, abbreviated as "Cites per Doc. (2y)", is another index that measures the scientific impact of an average article published in the journal. It is computed using the same formula as the journal IF.

Both of them have limitations and because of that we see many indicators to measure the quality of the journals.

Well it really seems that the Impact factor is important for many universities but it is not always true. Sometimes Publications outside this may be much more useful