The UPSC Civil Services Examination structure is unique compared to other competitive exams, consisting of three stages: Preliminary Examination, Mains Examination, and the Interview. The Preliminary stage is a screening test with multiple-choice questions to filter candidates, while the Mains focuses on written descriptive answers across various General Studies (GS) papers and optional subjects. Finally, the Interview assesses candidates' personalities and suitability for civil services. This multi-tiered approach, especially the emphasis on comprehensive understanding and analytical skills, distinguishes UPSC from many other exams that may only require objective reasoning or a single stage of assessment.