The group recently published an article in Physical Review Fluids (PRFluids); see Benzi’s blog, here: https://bit.ly/2NDCb0S. PRFluids is a relatively young member of the Physical Review family, with an esteemed editorial board, which is why we are proud to publish there. But how does it stack up against the more-established fluids journals? For example, Journal Fluid Mechanics (JFM), Physics of Fluids (PoF), and Physical Review E (PRE) — all of which we have published in within the last year or two.
This is a form of the common question “which journal is best?”, and the answer is in some sense simple: the best journal depends on the audience you are trying to reach. Given each journal has a subtly different remit and style, and hence readership, you should choose the journal that best suits the article’s intended audience. In reality, though, other factors come into play in decision making — a common one being the Impact Factor.
The Impact Factor (IF), also known as the cite score, is a well-known metric that measures the impact of the average article published in that journal. Specifically, the average number of citations an article published in the journal receives per year. There are many objections to using the impact factor to rank journals. First, in fields where there are many researchers (and more publications), the top journals receive many more citations than the top journals in smaller fields. For example, the publication Cell has an impact factor of around 27. By contrast, Journal of Sound and Vibration (the top journal in acoustics) has an impact factor of 3.7. Another objection to the IF is that it doesn’t take into account where the citations have come from — a citation from a prestigious journal should be worth more than a citation from a low-ranked one.
To combat some of these issues, numerous elaborate metrics have been proposed. The SCImago Journal Ranking (SJR) is one of them. The SJR methodology is similar to the Google PageRank algorithm and attempts to measure the ‘prestige’ of a journal. The source of citation transfers its own prestige to another source through the act of citing it. As such, a citation from a source with a relatively high SJR is worth more than a citation from a source with a lower SJR (all citations are not equal).
The graph below shows how SJR has changed over the past 20 years for the top fluids journals (and a middle-of-the-road one, for reference). What is clear is that, while JFM still seems to be top of the pack, the SJR (prestige indicator) for both PoF and JFM has dropped substantially. What might be the cause of this? The second plot shows the source documents published per year. Most notably, much more is being published by the top journals since 1996, and now PRFluids substantially adds to this (it hasn’t taken JFM or PoF’s market share). It is probably safe to assume that, while total research in fluids is growing, these top journals are collectively taking a greater proportion of the total output of fluid dynamics research nowadays; this means that there is less to differentiate them from the weaker journals (i.e. the prestige gap has reduced). What has driven this change (if true at all)? I suspect it’s a combination of financial incentives for publishers to publish more if there is demand, and increased pressure for researchers to publish only in the top journals.