The Impact Factor is calculated annually by Thomson Reuters for over 10,000 journals in their Journal Citation Reports (http://thomsonreuters.com/products_services/science/science_products/a-z/journal_citation_reports/). It is the number of citations to articles published in that journal in the last two years divided by the number of articles published in the journal in the last two years. More prestigious journals will have higher numbers as their articles are cited more frequently.

I'm not sure what the impact index is referring to, so it is difficult to compare the two as they might be measuring different things and without knowing what the journlas are I can't advise you which is "better".

What you can do though is look at tools like EigenFactor (http://www.eigenfactor.org/) and the SciMago Journal Rankings (http://www.scimagojr.com/) to compare how they list the two journals you're interested in. Or look through old issues and see what you think of the articles they publish.

I hope this helps,

Clari

1 The average number of citations to recent articles published in the journal. (Impact factor)

2. To maximize the visibility in publishing the top ranked journal. (Impact of indexed of journals)

2. Impact factors are calculated yearly for those journals that are indexed in the Journal (Difference)

As Clarissa Gosling says: The Impact Factor is calculated annually by Thomson Reuters for over 10,000 journals in their Journal Citation Reports (http://thomsonreuters.com/products_services/science/science_products/a-z/journal_citation_reports/). So the Impact Factor is a Thomson registry term and only includes journals indexed by ISI WEB OF SCIENCE Databases. Another Database that makes journals' measurement is SCOPUS, only for the journals they analize. You can read more information at SCIMAGO JOURNAL AND COUNTRY RANK: http://www.scimagojr.com/

I found these définitions from Buela-Casal (2010, http://www.ugr.es/~aepc/articulo/scientific.pdf)

Journal impact factor: This is calculated by dividing the total number

of citations made in one year to the papers published in a journal during the

two previous years, by the number of papers published in the journal during

that same 2-year period. Usually, this indicator only refers to the journals included

in the Web of Sciences (Buela-Casal, 2003; Garfield, 2003).

Advantages: Without doubt the most used and best known indicator in all

fields of scientific research. Used for assessing researchers, journals and institutions

in the majority of countries in the world.

Journal impact index: The same as the impact factor, except that it

also takes into account journals not included in the Web of Science.

Advantages: It is very useful for assessing and classifying many journals

not included in the Web of Science. It is particularly useful for cataloguing

national journals. See, for example, IN-RECS (http://ec3.ugr.es/in-recs/).

Disadvantages: The same as those described for the impact factor.

The journals which show impact factor (ISI impact factor) having suitable platform for submitting your manuscript.

The impact factor is the measure of the journal which is known by many scientists. The Impact index is new measure the new scientist is thinking about. This is to cover those journal which wer not on the web. Therefore, you need to be kin with the audience which will evaluate your paper.

quite confused about the term of impact index, it seems to be confusing with impact factor.

i feel the two are not same

so an impact index of 4 does not mean an impact factor of 4

B A Laway

Thanks to all for sharing views over Impact factor and Impact Index.

The term 'impact index' is used by predatory publishers like Photon to confuse people into thinking their journals are legitimate. Read about Photon here: 

http://scholarlyoa.com/2013/11/28/shedding-some-light-on-the-photon-foundation/

Impact factors are not great, but if journals have no impact factor at all they are likely not good places to submit your research to. 

Unfortunately, some invalid journals try to show their quality unlike reality. They use some fake indicators such as UIF (Universal impact factor) or IF provided by International Scientific Index. I believe you can choose your desired journal due to the publisher, impact factor (Thomson), SJR, editorial board, authors' institute and being disciplined.

There are two different measurement systems as I've taken a look at it.

journal-metrics.com

journalmetrics.com

ISI LIST Science 2014

Dear Chavhan, Dear RG colleagues,

Thank you so much for your important question, I think, you have to chose the journal with IMPACT FACTOR (IF) only furthermore, this selected journal MUST be indexed at the international academic site www.scimagojr.com, so you also have to avoid the untrusted or fake indices like JIF Journal Impact Factor and UIF Universal Impact Factor and others. Anyway, I am ready to help you in selection process.

Regards

Emad

http://www.scimagojr.com/

I am also confused, what is the difference between journal indexing and ranking? Are there other ranking bodies, I only know of Scimago? 

a good journal with an impact factor even if small should be indexed in Pubmed or Sciencedirect

I have a new thing. Thank you

Impact factor is important for ranking. 

An impact factor journal is one which has been issued an impact factor based on average citations on previously published papers. Most commonly it's the Thomson-Reuters ISI impact factor people refer to, for which you have to be indexed by Thomson ISI Web of Knowledge and be included in the ISI Journal Citation Reports (JCR). There are other, like SCImago Journal Rankings.

Some invalid journals try to show their quality unlike reality. They use some fake indicators as impact index provided by International Scientific Index.

Thanks a lot, its helpful

I wrote a paper on information literacy, can someone recommend me any free journal of information literacy to submit this paper, please. Thanks.