The reason why universities are so keen on the impact factor of journals is because it is an important parameter in comparing the status of different Universities in international lists. It is also very easy to evaluate a scientist because the impact factor is known as soon as the manuscript is published whereas several years are required to obtain the citation of an individual publication.

The impact factor of journals is not equivalent to impact factors in science. I have read that 20% of papers published in Nature are never cited. Another problem is that in some disciplines an inpact factor of 2 to 3 would be very high whereas in other disciplines that would be considered an average impact. There is another way around this difficulty i.e. that journals such as the BMC series records the accessions of manuscripts, this gives a quick idea of the interest and probable impact a publication would have.

Some journals not accredited by Thomson Reuters calculate their own unofficial citation index. These figures are always suspect because it is not calculated by an independent organization.

There are many metrics for journals and individual researchers. Elsevier's Scopus included SNIP (Source Normalized Index per Paper) and SJR (Scimago Journal Rank) metrics a while ago, but all these metrics should be handled carefully. Linked below is Elsevier's metrics site.

Google Scholar uses the individual researcher's h-index (Hirsch), see

http://en.wikipedia.org/wiki/H-index

http://www.journalmetrics.com/

Impact Factor (IF) is an indicator reported by Thomson Reuters (Formerly ISI) NOT other institutes. The others may copy IF from the original resource or provide old IF or fake info even there are predatory journals who provide fake IF or indicators with similar names to cheat. You can trust the reported IF of journals from famous publishers (Elsevier, Wiley, Springer, etc) but not all.

IF is calculated only for the journals indexed in one of the three citation indexes of Web of Science (all products of Thomson Reuters):

1. Science Citation Index Expanded (SCI-EXPANDED)

2. Social Sciences Citation Index (SSCI)

3. Art and Humanities Citation Index (A&HCI)

Since Thomson Reuters is the only authorized body to report IF. There is no other way to get IF. The only valid way to check IF is to see Journal Citation Reports (another product of Thomson Reuters).

Some of publishers such as BioMed Central (BMC) provide Unofficial Impact Factor for their journals but it never quarantines that the journal will get IF.

Thanks @Farhad Shokraneh @Dr. Devang Pandya.

However, how to find out journals that might have very good IF as compared to that of having authentic IF (provided by Thomson Reuters). We have many options for publishing articles, i.e., we have many publishers. But, only one organization to provide IF. Does Thomson Reuters work on its will? Where is competition?

As long as our institutions use IF as the single metric of academic success, there will be no competition. We just have to follow the rules, in case we want to raise our merits there.

In the meantime things are changing, as many colleagues anticipate it. Open Access might be a cure to monopoly, leading to new measures of academic success (many threads around here). And, as always, I point on 'Beall's list of predatory OA publishers' to avoid detriments using this emerging source for publication. Also have a look at DOAJ (linked below) to find OA journals with SNIP and Scimago index, which are more and more accepted.

http://www.doaj.org

As it has been said, IF is calculated based on the WoS indexed journals and you can contrast such measure with the indicators provided by other citation indexes, such as Scopus. It is ever limited to the framework of the journals used as reference to measure the impact. Maybe you should consider all of the information available (quantity of documents published, quantity of citable documents, gross quantity of citation in a given period of time) so you can have a more accurate view of the impact.

There are some 11,000 journals with IF, but over 21,000 with SNIP (Scopus based, by the Leiden CWTS on jurnalindicators.com) or SJR (also Scopus based, by SCImago on SCImagoJR.com). Just do not use them for evaluation of papers or researchers. And I suggest to choose a journal based on visibility and topicality and editorial quality.

@Jeroen, you say "do not use them for evaluation of papers or researchers". Two questions: (1) What do we use these metrics for, then? (2) How about the h-index - is it more reliable regarding individual researcher's "impact"?

@Michael

1) This is not just me by the way. Thomson Reuters itself and all bibliometricians repeatedly say impact factors should not be misused to judge individual papers or researchers. And now also swaths or scholarly organizations advise against i (see the San Francisco DORA declaration at http://am.ascb.org/dora/) IFs can still be used for what they were made for. i.e. to underpin decisions by libraries on what journals to subscribe to. Though I must say that even here IFs are not as useful as they used to be because of the fast growing number of journals without IF and because the IFs correlation with citation rates is diminishing..

2) H-indexes are better in the sense that they can reflect an individual's impact based on that individual's papers only. But the h-index reflects impact AND production. It has serious flaws. One is that it doesn't recognise the genius with few but very highly cited papers (Einstein would never have been hired). Another is that it can only rise. A previously prodigious and influential researcher that hasn't done anything worthwile for years retains his/her high H-index. Finally the H-index has some counterintuitive mathematical properties that may render it unfair for comparing people in some cases.

Thank you for this clear statement, Jeroen. The question remains why so many institutions evaluate individual researchers with the help of IF.

That puzzles me as well. It may have to do with the lure of numbers and their air of objectivity. As long as you use numbers and the perceived quality of peer review of journals you can not be blamed of being subjective. But of course these are just my guesses as to what is going on..

Three important points regarding the use of bibliometric indicators.

http://www.ieee.org/publications_standards/publications/rights/bibliometrics_statement.html

I think the universal and currently accepted measure of journals is impact factor by Thompson Reuters

The emergence of Open Access Journal System has now started propagating other assessment by other indexing agencies (eg: Index Copernicus, Indian Citation Index....)

This is just because Thompson Reuters i believe has a stringent mechanism ( I have also noted some publisher are getting in to Thompson Reuters even at their infancy and many journals are not covered

The reason why universities are so keen on the impact factor of journals is because it is an important parameter in comparing the status of different Universities in international lists. It is also very easy to evaluate a scientist because the impact factor is known as soon as the manuscript is published whereas several years are required to obtain the citation of an individual publication.

The impact factor of journals is not equivalent to impact factors in science. I have read that 20% of papers published in Nature are never cited. Another problem is that in some disciplines an inpact factor of 2 to 3 would be very high whereas in other disciplines that would be considered an average impact. There is another way around this difficulty i.e. that journals such as the BMC series records the accessions of manuscripts, this gives a quick idea of the interest and probable impact a publication would have.

Some journals not accredited by Thomson Reuters calculate their own unofficial citation index. These figures are always suspect because it is not calculated by an independent organization.

The idea of insisting on impact factor of a journal raises many questions. First, should the emphasis be on impact factor or impact Quality?  What of journals that are highly rated internationally that drill academics on how to write good articles but do not have impact factor, should they be discarded? For instance, William and Mary Quarterly is one of the standard journals any historian would aspire to publish in but it has no impact factor. Compare article in William and Mary Quarterly with that of some with impact factor - the difference is clear. Another issue is that local journals based in some African and Nigerian universities where the works of the like of Chinua Achebe appear are not made to count as they do not have impact factor. This raises another question as to whether local content is no longer important as it would promote indigenous knowledge. 

The whole scientific publication field is busy changing drastically because some of the open impact journals are mainly interested in making money.  Some of the traditional journals without page charges could only survive if they had a good stature and if University Libraries subscribed to the journals.  Because it is much more expensive to produce a printed journal and there is only a limited number of pages some of these journals have close to a 90% rejection rate, frequently before sending manuscripts out  for reviewing.  

This opened the way for expanding open access journals.  This number is multiplying I have been noting the number of different journal that have asked me to review papers during the past five to ten years.  It now stands at 263 different journals in the field of medicinal plants.  Some of these journals are good, but their citations are not reflected in WOS (ISI) rated journals therefore the impact factor by WOS cannot increase.  

There are also a number of journals that are just trying to get money from authors.  See http://scholarlyoa.com/2012/12/06/bealls-list-of-predatory-publishers-2013/

for a list of predatory journals. 

If you do not have really good results and you cannot publish it in an WOS/ISI rated journal, I propose that you  search for the citation of another potential journals looking at Google Scholar.  This theoretically  includes everything that is on the internet.

At least then you would now that it is not a predatory journal that takes your page charges and never publishes anything and you may build up your personal citations in Google scholar by publishing in that journal.

Dear colleague

The term "impact factor" is a Thomson Reuters' index. The thomson Reuter's IF is the only accepted and used impact factor. a journal with impact factor must be in the JCR or one of the Thomson Reuter's master list.

Best regards

Bachir

Should worked more

I want to mention that few open access journals are free. There is no publication fee after acceptance. 

Impact Factor (IF) is an indicator reported by Thomson Reuters (Formerly ISI) NOT other institutes.