The Thinking Skills selective test and OC section: question types and how to approach them

By Jon Petruch · Official details checked 21 October 2026

The Thinking Skills selective test section, which also appears in the OC test, is the one parents find hardest to explain, because it doesn't match a school subject. It tests critical thinking and problem solving through multiple-choice questions, about one per minute. This guide explains how it works in each test, the question types in the department's own practice papers, and how to help your child handle them.

What is the Thinking Skills test?

Thinking Skills is one of the multiple-choice sections in both NSW placement tests: the OC test in Year 4 and the selective test in Year 6. It tests general critical thinking and problem-solving ability, and the NSW Department of Education says no previous knowledge is needed.

That's what makes it different from Reading and Mathematical Reasoning. There's nothing to revise, so a child's result depends on how they reason through unfamiliar problems.

How is Thinking Skills different in the OC and selective tests?

The selective version is longer, with 40 questions in 40 minutes, while the OC version has 30 questions in 30 minutes. Both use four answer options and allow about one minute per question.

The figures come from the department's OC practice tests page and selective practice tests page. In the department's example timetables, Thinking Skills is the last OC section and comes after the snack break in the selective test.

What types of questions are in Thinking Skills?

Thinking Skills mixes two families of question: critical-thinking questions about arguments and reasoning, and problem-solving questions built on numbers, patterns and shapes. In the department's selective Practice Test 1, the two families are mixed together rather than grouped, so children switch between them from one question to the next.

The question types that recur in that paper are:

• Strengthen or weaken: which statement, if true, most strengthens (or weakens) an argument
• Spot the mistake: which sentence shows the mistake a person has made in their reasoning
• Whose reasoning is correct: two people draw conclusions from the same facts, and the child decides who is right
• Must be true: what follows for certain from a set of statements, or what is not possible
• Number puzzles: multi-step problems about ages, scores, money or groups
• Spatial and pattern questions: views of an object from another side, pieces that fit together, sequences on a display

The department notes its PDF papers come from the older paper-based test, so the format differs from today's computer test. The question styles are still the best official guide to what your child will see.

What is a strengthen or weaken question?

A strengthen question gives a short argument and asks which new fact, if true, would most support its conclusion; a weaken question asks which would most undermine it. The trick is to find the argument's conclusion first, then pick the option that bears on the reason given for it.

In the official paper, wrong options are often true-sounding or on topic but don't touch the reasoning, such as a statement about the same subject that doesn't affect whether the conclusion follows. Children who pick the most interesting or agreeable statement fall into this trap.

What are the reasoning and mistake questions?

These questions give a rule or a set of facts and ask whether someone's conclusion actually follows from them. Some ask which sentence shows the mistake a person made; others give two people's reasoning and ask whether one, both or neither is correct.

The most common mistake they test is reversing a rule. If everyone who missed the spring concert will play in autumn, that doesn't mean everyone who played in spring won't. Adults make this error all the time, which is why a capable ten-year-old can find these questions harder than they look.

What are the problem-solving questions like?

Problem-solving questions are multi-step puzzles: working out ages from clues, tracking marbles passed between players, finding the cheapest valid combination, or picking a possible side view of an object. They use Year 6 maths at most, but they need careful organisation more than calculation.

A child who writes the clues down and tests options one by one usually does better than one who tries to hold everything in their head. In the computer test, children get paper for working out.

Why do capable students find Thinking Skills hard?

Thinking Skills is hard for many strong students because the reasoning it tests isn't taught as a school subject. A child can be at the top of their class and still meet these question types for the first time under exam timing.

From Jon: In my experience, NSW primary schools don't necessarily teach the logic skills that Thinking Skills questions rely on. That makes sense, because the department designs the test to measure a child's current ability rather than something they've been taught. But it means a bright child can be meeting "which statement most strengthens the argument?" cold, with one minute on the clock.

The department's position is that coaching is not necessary and gives no advantage. Its own practice tests exist so the question types aren't new on the day, and that familiarity is the realistic goal.

How should my child handle the one-minute pace?

Your child should answer every question, because the department's practice papers state that students won't lose marks for incorrect answers. With about one minute per question, it's better to make a reasoned guess and move on than to spend three minutes on one puzzle.

A good habit is to flag long number puzzles and come back to them, since a short argument question is often quicker. Practising under a timer is the only way to learn what one minute feels like.

How can my child improve at Thinking Skills?

Start with the department's free online practice tests for the OC test or the selective test, then go through the explanation of answers for every question your child got wrong. Understanding why an option is wrong builds the skill faster than doing more questions.

Talking through everyday arguments helps too: ask your child what reason someone gave, and whether it really supports what they said. If you want more timed practice than the official set, our OC practice tests and NSW Selective practice tests include Thinking Skills with worked explanations. No preparation product can guarantee a place, and we don't claim ours will.