I have been working on writing a research proposal. So, it seems to me that the research gap and justification are the same things. So, I need suggestions from the expert to know whether I am correct or not.
Research justification = 'problem' statement. The goal of the first step of the research proposal is to get your audience's attention; to show them why your research matters, and to make them want to know more about your research.
Rationale and justification of your research are essentially the same thing - they provide a background context and an argument for why your chosen topic is interesting, important, original and viable. However, the discussion of the research gap is only a justification for originality.
No they are not similar. let me start with an example here; you can not justify your research by saying that "due to the inconsistency result of prior studies you are intending to do yours, or because this work have not been done before. or previous studies used small sample...and so on. these can be refereed at as gaps in the literature.
To justify your research, usually is linked to practice problem, and how your research going to solve that problem and help the 'research population'. your research justification should also be at the first few paragraph of your problem statement. then you can mention the research gaps.
Some believe that, but it can be said that the research gap is the notes that the researcher diagnoses, which may be considered a mistake that should be avoided