Analytical Ability: Syllogisms, Assumptions & Analogy Formulas

Techniques for identifying valid deductive conclusions, Venn diagram mapping for categorical syllogisms, and single-word analogies.

ReviewTayo Editorial Team(Civil Service Exam Curriculum Researchers)

Last updated: September 2026

Categorical Syllogisms & Venn Diagram Mapping

Syllogisms test your ability to determine what necessarily follows from given premises, ignoring real-world truth. Rule 1: 'All A are B' means circle A is entirely inside circle B. Rule 2: 'Some A are B' means circle A and circle B intersect (at least one member shared). Rule 3: 'No A are B' means circles A and B are completely disjoint. Crucial tip: If a conclusion is merely possible but not guaranteed by the premises, it is invalid.

Key Takeaways for Examinees

Accept premises as true even if they sound contrary to factual reality.
'Some' in formal logic means 'at least one', not necessarily 'less than all'.
Two negative premises yield NO valid categorical conclusion.

Sample Exam Simulation Question

Premises: (1) All accountants are meticulous. (2) Some auditors are accountants. Which conclusion necessarily follows?

A. All auditors are meticulous.

B. Some auditors are meticulous.

C. No auditors are meticulous.

D. All meticulous people are auditors.

Concept Rationale: Since some auditors are accountants, and every single accountant is meticulous, those auditors who are accountants must also be meticulous. Hence, 'Some auditors are meticulous' necessarily follows.

Official Syllabus References & Legal Authorities

Civil Service Commission Examination Announcement: Test Scope & Guidelines (Analytical Ability - Professional Level)(Civil Service Commission (CSC))

Apply what you learned

Practice specific Analytical Ability questions in timed examination conditions.

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