What is the relationship between impact factor and journal ranking As a second year graduate student, it's become increasingly difficult for me to figure out what journals are the most prestigious.  My research is very interdisciplinary, and so journals from many different fields would be suitable for my work.

Initially, I took Impact Factor as a good proxy for journal ranking.  However, I've come to learn that IF doesn't necessarily reflect the whole story.  It seems that number of citations (for an individual publication), regardless of journal, appears to be the most important metric.

However, barring that, I assume most people (in the interest of career success), would still like to publish in the best journal they can get in.

Consider a journal like Physical Review Letters.  It has an impact factor of 7.7.  However, a relatively new journal like Advanced Energy Materials has an impact factor of 14.3, almost double that of PRL.  However, I've always heard that PRL is one of the best physics journals that you can publish in (heck, Einstein's EPR experiment was published there).  So if I had an article that would be appropriate for submission to both, which would be the better one to get in?

Then there's something like Nature Physics, with its 20.6 Impact Factor, which suggests getting in here would be a more significant achievement that either of the other two.  But by how much?  Surely not by three times?

(Part of the problem is that Research Gate gives you a total IF score for all your publications, which I think biases that number more than it should be.)
This is a particularly difficult question for interdisciplinary research, because different fields have radically different citation customs and publication time-tables, which leads to the same impact factor meaning very different things. Impact factor also has numerous other problems.

Moreover, absolute ranking of a journal is in many cases less important than reaching the audience that you want to talk to, particularly in interdisciplinary research and especially if you want to reach an application community.

Rather than focusing on impact factor, I would recommend using the following method to determine how to rank journals as possible publication targets: 


Pick half a dozen researchers who you highly respect and want to be the audience for this paper.
Look at the journals that they publish in.  The more frequently a journal appears, the better it is as a target for this audience.


This can also help you distinguish between targets for broad and narrow papers.  For example, you might have a methodology paper that speaks to a very particular sub-discipline.  A journal specifically for that sub-discipline may have a much lower impact factor, but may be a much better place to place the paper and it may actually end up having much higher impact and citations than if it is in a "better" venue where it is mostly read by people for whom it is irrelevant.