OC Thinking Skills: The Reasoning Test Explained

Thinking Skills is the section that surprises parents most. It's a logical reasoning test — closer to a puzzle than to school maths or English — and it's often what separates OC candidates, because you can't cram facts for it. It's part of both the OC test and the Selective test.

What the Thinking Skills section is like

• Around 30 questions in about 30 minutes.
• All multiple choice, each based on a short scenario or argument.
• No curriculum content — it tests how a student reasons.

The reasoning it tests

• Drawing conclusions — what must be true given the information.
• Identifying assumptions — the unstated thing an argument depends on.
• Spotting flaws — why an argument doesn't quite work.
• Logical deduction — "if A is taller than B, and B is taller than C…" puzzles.
• Patterns and problem-solving — working systematically to the answer.

A quick example

"Every student in the choir can read music. Mia can read music." Does it follow that Mia is in the choir? No. The statement says choir members can read music — not that everyone who reads music is in the choir. Recognising that gap is exactly the skill being tested.

How to prepare for Thinking Skills

• Practise the question types so the format is familiar — the reasoning is learnable with exposure.
• Read the argument twice and separate what is stated from what is assumed.
• For deduction puzzles, jot a quick diagram or ordering rather than holding it all in your head.
• Play logic games — sudoku, riddles, strategy games all build the same muscles, painlessly.
• Do timed sets so 30 questions in 30 minutes feels comfortable.

Practise Thinking Skills–style reasoning free in OC practice, and see common reasoning mistakes to avoid.