An argument question asks which statement makes a claim stronger or weaker, judging the reason only. Children in Year 3 now sit the OC test in Year 4, on 11–12 May 2027.
An argument is a claim backed by a reason. "We should water the garden in the morning, because afternoon sun dries the water up" has two parts: the claim (water in the morning) and the reason (the sun dries the water up).
Judging it means asking one thing: does the reason really prove the claim? Your child acts like a fair judge, and their own opinion about gardens, fruit or reading doesn't count. Only the reason and its link to the claim count.
How do argument questions show up in the OC Thinking Skills test?
Your child reads what one child says, then picks the statement that most strengthens it, most weakens it, or shows the mistake in it. The Department says Thinking Skills checks critical thinking and problem solving, with no previous knowledge needed, and the section has a range of question types, shown in the practice tests.
The OC Thinking Skills test
What it means for arguments
30 questions in 30 minutes
About a minute each, so read the claim carefully, once
4 options each
Test every option against the reason, not your own view
There are no marks lost for incorrect answers
A careful guess always beats a blank
The Department doesn't publish a fixed list of question types. Judging arguments is how our lessons group these questions.
Four steps, in the same order every time. Your child can point at each part on the screen as they go, which keeps their own opinion out of it.
Read the job
Does the question ask what strengthens, what weakens, or what the mistake is? Each one needs something different.
Find the claim
What does the speaker want everyone to believe? Words like should and so often mark it.
Find the reason and the gap
What evidence is given? Then ask: what else must be true for this reason to prove the claim?
Test each option against the gap
A strengthener fills the gap. A weakener shows another explanation. An option that doesn't touch the gap is out.
What do OC argument questions look like?
Three questions from easier to harder: one strengthens, one weakens, and one asks for the mistake.
Each one shows the answer and the working, so read them with your child. The explanation says why each wrong option is wrong: ask your child which one looked right at first, because that's the habit to fix.
Worked explanation 1
Mia says: "Our class should water the vegetable garden in the morning, not in the afternoon. In the afternoon the sun is hot, so a lot of the water dries up before the plants can use it."
Which one of these statements, if true, most strengthens Mia's argument?
AA.
Beans and tomatoes are the easiest vegetables to grow at school.
BB.
The garden has a tap right next to the classroom door.
CC.
Our class has more free time in the afternoon than in the morning.
DD.
Water given in the morning soaks deep into the soil before the day gets hot.
Answer: D
Answer: D (morning water soaks deep into the soil before the day gets hot)
Mia's reason is that afternoon water dries up before the plants can use it.
To make her argument stronger, we need evidence that morning water does reach the plants.
D says morning water soaks deep into the soil before the day gets hot, so the plants get to use it. That backs up her choice of the morning.
Why the other options are wrong
A: This is about the garden, but it says nothing about when watering works best.
B: Where the tap is does not change whether morning or afternoon watering is better.
C: This is a reason to water in the afternoon, so it makes Mia's argument weaker, not stronger.
Worked explanation 2
Ella says: "Students at our school do not like fruit. The canteen sells fruit cups every day, but hardly anyone buys them."
Which one of these statements, if true, most weakens Ella's argument?
AA.
The fruit cups are kept in a fridge behind the counter, out of sight.
BB.
Pies are the food that sells best at the school canteen.
CC.
The canteen opens before school starts and again at lunch.
DD.
When free fruit is handed out at sport, most of it is left over.
Answer: A
Answer: A (the fruit cups are kept out of sight)
Ella's only evidence is that hardly anyone buys the fruit cups.
A gives another reason for the low sales: the cups are kept in a fridge behind the counter, out of sight, so students may not even know they are there.
So low sales no longer show that students dislike fruit.
Why the other options are wrong
B: Knowing which food sells best tells us nothing about why so few fruit cups are bought.
C: When the canteen opens does not explain why so few fruit cups are bought.
D: Leftover free fruit suggests students really do not want fruit, so this makes Ella's argument stronger.
Worked explanation 3
Each team in the class reading challenge has 4 children. This week, Team Koala finished 9 books and Team Wombat finished 6 books.
Aisha from Team Koala says: "So more children in Team Koala finished a book this week than in Team Wombat."
Which one of these sentences shows the mistake Aisha has made?
AA.
Both teams have exactly the same number of children in them.
BB.
Team Koala might finish fewer books than Team Wombat next week.
CC.
One child in Team Koala could have finished several of the 9 books.
DD.
The books Team Wombat read might have been longer than Team Koala's books.
Answer: C
Answer: C (one Koala child could have finished several of the books)
Aisha counts books, but her conclusion is about children.
9 books do not have to mean 9 different readers. One Koala child could have finished several books while the others finished none.
For example, if one Koala child read all 9 books, only 1 Koala child finished a book, while all 4 Wombat children might have. So more books does not prove that more children finished a book.
Why the other options are wrong
A: This is true and is given in the information, so it is not a mistake in Aisha's thinking.
B: Aisha is only talking about this week, so next week does not matter.
D: Longer books might explain why Team Wombat finished fewer, but Aisha's claim is about how many children finished a book.
Which argument mistakes cost marks?
Most wrong options are true and on the same subject, but they don't touch the reason. Each has a quick check your child can run before choosing.
×
Picking the option you agree with: ask only whether it changes how well the reason proves the claim.
×
Choosing a fact that is about the subject but not the reason: if it says nothing about the speaker's evidence, cross it out.
×
Mixing up what the evidence counts and what the claim is about: books finished is not the same as children who finished a book, so check the claim's exact words.
What does the Judging Arguments lesson cover?
Judging Arguments (lesson preview)
A short preview from the SelectiveReady lesson “Judging Arguments”, on judging arguments for the NSW Selective test.
Published:
Read the video transcript
And that brings us to option B. The studies were only done in one school. And there it is. Ding ding ding. This is the one we're looking for. This is the statement that actually weakens the argument. So why? What's the deal here? It's because it directly attacks the strength of the evidence itself. And this slide just shows the flaw so perfectly. The premise, the evidence, right? It comes from this teeny tiny data set, just one school. But the conclusion? It's this massive sweeping recommendation for all schools everywhere. A good judge spots that mismatch in a heartbeat. The evidence is way too narrow to support such a huge conclusion. The argument is logically weak. Case closed. See?
The preview, with English and Chinese captions, finishes a question by showing why one option weakens an argument: the evidence came from a small group, but the claim was about everyone.
The full lesson in the SelectiveReady app adds the parts of an argument, a strength checklist and the common traps. A free account opens one lesson, How and Why Authors Write; the other lessons need a paid plan.
How can my child practise judging arguments for free?
Start with Practice test 1, which has Thinking Skills at its real length and time. It's one full practice test with results, with a free account. Every answer is explained, and the results by skill show whether your child loses marks on judging arguments.
After that, the app has drills by section and topic; a free account drills the free test's questions, and a paid plan opens the rest. At home, test everyday claims together: an advert, a school note, a sibling's reason for a later bedtime. Ask what the reason is, and whether something else could explain it.
