When a project reaches the publishable stage, it is time to mull over the question: To which journal should the manuscript be submitted?
In some cases this question needs to be answered at the very earliest stages of manuscript preparation, as the answer may govern fundamental aspects of manuscript content, style, and length. In other cases -- e.g. when there are several likely options that aren't dramatically different from each other in focus or impact factor -- the answer can wait until the manuscript is underway, though I like to figure out the target journal fairly early in the process if possible.
For most manuscripts, I have any easy time figuring out the target journal. In some cases, however, there are several reasonable possibilities and it can be difficult to choose. These situations tend to involve projects that don't easily fit into the traditional specialized categories of my field or are projects in which I am a minor participant.
I don't think my journal-decision making process is any different now than when I was an early-career scientist because I am still publishing in the same journals. The advent of search engines and citation indices has shifted the publishing ecosystem in many ways, but the esteemed journals are still the esteemed journals, and you need to publish in them if you want colleagues to respect your work.
Despite the tyranny of citation indices and h-indices and so on, the plus side of indexing is that it is somewhat less important where you publish, as long as your paper is indexed. A paper in a random highly-specialized journal is perhaps somewhat less likely to sink into obscurity than it might have been during the print-only days. Perhaps.
Fortunately there are many appealing options between the high-impact monosyllabic-titled journals and Journals of Last Resort. It's good to be able to choose among an array of journals that are widely read and respected, so that best-fit considerations can guide the decision.
When making the Journal Decision, I also take into account my opinions about the editorial process of a journal. Some journals are extremely slow; I try to avoid these if possible, though that isn't always possible. Some journals have insane editors. Ditto. But journals can change through time. Slow editorial systems can become more efficient, and formerly good journals can sink owing to insane and/or slow editors or other random factors. You can figure out which is which through experience and by talking to colleagues and others.
As I was thinking about this topic, I realized I had no idea how many journals I have published in during my career beyond having a feeling that it was more than a few. So I counted them (including only published papers, not manuscripts in review) and the number is in the twenties.
If I don't consider the journals in which I've published only once, the number drops by about 1/3. Some of those 1-paper journals were co-authored with colleagues who publish in a different field and my involvement in this type of research began and ended with one project; others were random projects that ended up in somewhat obscure, highly-specialized journals for various reasons (e.g. special issues related to a conference).
I actually don't know if my Journal Number (JN) is high or low. I suspect it is high but not absurdly high compared to the JN for other researchers in my field, as there are many possible journals in which our type of research can be published. If it is on the high side, this may be because my work tends to be fairly interdisciplinary, opening up even more possibilities for suitable journals.
So, for most papers my decision about where to publish can be summarized as follows, keeping in mind that the journal pool I am discussing in this general case consists of top-tier (if not stratospheric-tier) journals and that minute differences in impact factor of a journal are not important in my decision:
(1) I consider the range of possible journals for the topic; this is typically a number > 2 but < 10;
(2) I consider whether one more more are a slightly better fit for the topic owing to other papers published in that/those journals; in some cases this decreases the number of possible journals and in some cases it doesn't;
(3) I consider my recent experiences with a journal in terms of the editorial process, or, lacking my own data, I consult with colleagues or I look at recent papers to calculate a typical submission-to-publication time;
(4) I look at the journal's format re. publishing papers online early and other logistical aspects of the submission and publication process, though there is really only one journal whose submission/manuscript processing methods are so abhorrent to me that it will be a long time before I submit another manuscript there;
(5) I consider whether other papers on related topics have appeared in certain journals; some journals can develop a micro-niche for certain topics;
(6) I consider where I have published recently; if I haven't published in a particular journal for a while and if there is no good reason not to send the manuscript there, I may decide it's time to try for another Journal of X paper, just for variety, even though that's probably a bit irrational;
and then I decide.
8 years ago