Q: Should we decide the target journal before the research is conducted?

You need not select a target journal before you conduct your research, although it would be helpful if you have a general idea about some of the good journals in the field.

However, it would be good if you can shortlist a few target journals around the time you start writing your paper. This will help you understand and follow the style preferred by your target journal. It is crucial that you select a peer-reviewed journal which will present your research in the best way and convey it to the right target audience.

The impact factor should not be your only criteria for journal selection. You should consider a host of other factors such as the scope of the journal, readership, visibility, and turnaround time. Additionally, it is always good if you have a list of 3-4 shortlisted journals. That way, even if your paper gets rejected, you will know where to submit it next and will not lose time in selecting another journal.

Here is an interesting inforgraphic that will give you more information on selecting a target journal.