Relevant research methodologies for selection in the UPSC exam include qualitative and quantitative analysis, case studies, and field research. Candidates should adopt a mixed-methods approach, synthesizing both qualitative insights and quantitative data to understand complex political, social, and economic issues. This comprehensive methodology helps prepare for both objective and subjective aspects of the exam. Additionally, honing skills in synthesizing diverse research materials enhances critical analysis capabilities, which are essential for writing comprehensive answers and essays in the examination.