Impact factor et al. for the Chinese Journal of Physics...
Journal Metrics
CiteScore: 0.78
Impact Factor: 1.051
5-Year Impact Factor: 0.821
Source Normalized Impact per Paper (SNIP): 0.449
SCImago Journal Rank (SJR): 0.216
Hey could you put that interesting data into some sort of context - like comparing it to a top of line physics journal and a moderately successful one?
Thanks in advance
No problem.
Impact factor is the headline measure, and is fairly simple. It's the average number of citations per article from that journal over 2 years. The 5-Year impact factor is the same, but over 5 years.
A run of the mill journal would have an impact factor of anything up to 3 or 4, a top journal could easily be in double figures, say 11 or 12 and the highest can be in the 20s. The lowest are usually around 0.2.
For instance:
The Journal of High Energy Physics has an IF of 5.54 (2017) and a 5-year IF of 4.99
The Astronomy and Astrophysics Review has an IF of 8.22 (2016) and a 5-year IF of 12.83.
The source normalised impact (SNIP) is weighted by the total number of citations in the field, so that helps you to compare to other journals in the same field of research more directly, while the SJR is similar, but also takes into account the IF of the journal the citing paper is in. (SNIP isn't always available for all journals)
The Astronomy and Astrophysics Review has a SNIP of 2.86 and SJR of 3.63.
The Journal of High Energy Physics has a SJR of 1.227 (couldn't find its SNIP)
The highest SJR is 61.786 for "CA a Cancer Journal for Clinicians", while Nature Materials gets 18.263, and Nature Physics 9.791 (IF 22.727).
Simply put, the lower the numbers are the less read the journal is, and the fewer the citations any article in it is likely to get. If you have something important and it will pass muster scientifically you submit it to a high impact journal so that it will be more likely to get seen and paid attention to. High impact journals are also generally far stricter about quality of peer review.
These aren't hard and fast rules, but they are indicators.
So why do low IF journals even exist? Well, some are used for very niche disciplines. How many people do you think will be interested in "Mathematical Fluid Mechanics" or "Thermophysics and Aeromechanics"? these journals are used for interesting results and science in subjects that won't get much attention outside the specialism. Nothing ground-breaking, but could be very good science and important to the narrow
Others are published by particular institutes, countries or national societies. These are usually where people publish stuff that wouldn't get into the higher impact journals because it simply isn't important enough, isn't really relevant or simply isn't good science. It's also where you'd bury something if you wanted to be able to say that you published, but didn't want actual scientists tearing it to shreds!
Bottom line, if Mills actually had something he could back up with hard numbers that mean something he'd publish it in Nature Physics, and they'd practically bite his arm off to publish it. The number of citations that that paper alone would produce would kick their IF way up the charts (and they're pretty high up there already).
But instead he publishes in a low IF journal, published by the National Physical Society of Taiwan, where hardly anyone will ever read it, and nobody (except possibly Mills himself) will ever cite it.
Ultimately the measure of how good any individual paper is, is in the number of citations from people who aren't directly associated with the authors. For Mills papers, that number is extremely low - other than Rathke (who wrote a scathing review) I don't know of anyone else, who isn't in Mills circle, citing his papers.