Q: In research, what is the basis difference between the rationale and the justification?
Actually, there is no difference between the rationale and the justification of the study. Both mean the same thing; the terms are used interchangeably. :-)
You may learn more about the rationale/justification of research through these resources:
- Can you give an example of the "rationale of a study"?
- How to write the rationale for research?
- What is the justification of a research?
As the rationale/justification is written in the Introduction of the paper, you may find this handbook helpful: How to write a strong introduction section that makes a great first impression
Hope that helps!