The Best English Books SSC CGL exam is conducted in four stages - Tier I, Tier II, Tier III, and Tier IV. Tier I and Tier II are computer-based exams, while Tier III is a descriptive paper, and Tier IV is a skill test. Candidates who qualify in Tier I can appear for Tier II, and those who clear Tier II can appear for Tier III. Tier IV is a qualifying exam, and the marks obtained in this stage are not considered for the final selection.