Q: How is research justification or justification of a study written?
The rationale or justification for doing any research must be gleaned from the existing literature on the subject. You will need to conduct a thorough literature survey and identify gaps in the current literature. The best way to write this is to introduce the current literature in the background/Introduction section and then highlight the gaps in the literature that have not been addressed or are yet to be understood. This will help set up the need for the current study and thus justify the need for this research.