Strengthen and Weaken Questions in Thinking Skills: How to Find the Best Answer
Learn how to solve strengthen, weaken and support questions in NSW OC and Selective Thinking Skills. Understand common distractors, hidden assumptions and…
Strengthen, weaken and support questions are an important part of NSW OC Thinking Skills and NSW Selective Thinking Skills. They can look deceptively simple because students are usually given a short argument followed by four statements.
The difficult part is that the question does not simply ask:
“Which statement is related to this topic?”
It asks:
“Which statement, if true, MOST strengthens, MOST weakens or BEST supports the argument?”
That one word, most, makes a big difference.
After reviewing the published OC and Selective Thinking Skills papers, a common pattern appears. Several options may sound sensible, and sometimes two answers genuinely have some effect on the argument. The student's job is to identify which one affects the central reasoning most directly.
These argument-evaluation skills are useful across both NSW OC practice tests and NSW Selective practice tests.
What is an argument in a Thinking Skills question?
An argument normally contains two important parts:
Reason or evidence → Conclusion
For example:
Exercise improves concentration.
Therefore, students who want to improve their chess performance should exercise regularly.
The first statement provides a reason. The second is the conclusion the speaker wants us to accept.
A strengthen question asks:
What new information would make the conclusion more convincing?
A weaken question asks:
What new information would make us less confident in the conclusion?
This sounds straightforward, but students often focus on the subject instead of the argument.
If a question is about exercise and chess, an answer about exercise may seem relevant. But unless it helps connect exercise to better chess performance, it may not strengthen the actual argument.
That distinction appears repeatedly in the published papers.
The most important skill: find the conclusion first
Before looking carefully at the options, students should ask:
What exactly is this person trying to convince me of?
Try reducing it to one short sentence.
For example:
“Students should be allowed to choose their own books.”
Now look at why the person believes that.
A statement such as:
Students learn more when they enjoy what they read.
provides a strong bridge between choice, enjoyment and the educational benefit of reading.
By comparison, learning that several other students also disliked the assigned book is relevant to the discussion, but does not show that allowing choice would improve learning. This distinction between a direct reason and a merely related fact is common in OC support questions.
Why two options can both look correct
This is probably the biggest difficulty in strengthen and weaken questions.
Students may narrow the choices to two and think:
“But both of these are true.”
That is not the test.
Every option begins with “if true”, so students should temporarily accept each statement as true. The question is:
Which true statement has the greatest effect on this particular argument?
Consider a general claim such as:
Fixing leaking taps is the most effective way to reduce household water waste.
Two possible statements might be:
leaking taps are easy to repair
leaking taps are the largest source of household water waste
Both sound supportive.
However, easy to repair tells us something about convenience. It does not establish that fixing leaks will reduce the most water.
If leaking taps are the largest source of waste, that directly supports the words “most effective”.
This exact kind of distinction appears in the OC material.
A useful question to ask
When two answers seem possible, ask:
“If I could keep only one of these facts, which one would make the argument noticeably stronger or weaker?”
The answer with the larger logical impact is normally the better choice.
Common distractors in strengthen and weaken questions
Across the papers, several distractor patterns appear repeatedly.
1. The answer that is relevant to the topic, but not the conclusion
This is extremely common.
Suppose someone argues that performing in school concerts is valuable for children.
A statement saying that many people enjoy watching concerts is clearly related to concerts, but it does not tell us why performing benefits children.
Evidence that performing helps build confidence directly supports the reason for giving children this opportunity.
Students should therefore ask:
“Does this option support the argument, or does it simply mention the same subject?”
Topic relevance is not enough.
2. The answer that actually works in the opposite direction
Some distractors are related to the issue but would actually strengthen an argument you are supposed to weaken, or weaken one you are supposed to strengthen.
For example, an argument might say competitive sports create unhealthy rivalry and PE should also include non-competitive activities.
A statement describing an important benefit of competitive sport does not strengthen that argument. If anything, it gives a reason to retain competitive sport.
Another statement showing that non-competitive activities can still provide the fitness benefits expected from PE is much more directly supportive.
This is why students should circle or mentally emphasise:
STRENGTHEN
or
WEAKEN
before comparing the options.
3. The answer that provides a side benefit, but does not address the reason
A person may recommend an activity for one specific reason.
For example:
Swimming should be added to running because it strengthens more of the body.
Statements about swimming being relaxing, useful for personal safety or enjoyable may all be positive.
But they do not support the specific reason given.
Evidence that swimming uses more muscle groups directly strengthens that argument.
A good rule is:
Follow the argument's reason, not just its conclusion.
4. The answer that attacks the key assumption
This is especially important in weaken questions.
An argument often relies on something that has not actually been proven.
For example:
More crashes happen between 4 pm and 7 pm, therefore an individual driver is more likely to have a crash during those hours.
There is a hidden assumption that roughly the same number of people drive at each time.
But what if far more cars are on the road between 4 pm and 7 pm?
Then the total number of crashes could be higher even though the risk to each individual driver is not higher.
This is a classic base-rate problem in the Selective material.
When weakening an argument, ask:
“What is the writer assuming must be true for this conclusion to work?”
Then look for the option that breaks that assumption.
5. The alternative explanation
Many weaken questions present evidence and then assume there is only one explanation.
For example:
X happened after Y, therefore Y caused X.
A powerful weakening answer may show that Z could also have caused X.
This pattern appears repeatedly in reasoning questions across the papers.
If an argument says a particular result proves one cause, students should immediately ask:
“Could something else explain the same result?”
Alternative explanations are particularly powerful when an argument uses words such as:
because
caused
therefore
must be
proves
clearly shows
6. The answer that is plausible but weaker than another answer
This is the most sophisticated distractor.
In a Selective weaken question, an argument claimed that space research was not useful because it did not improve life on Earth.
One possible option involved research that could help people grow plants elsewhere in space. That makes space research sound useful, but it does not directly answer the criticism about life on Earth.
Another option showed that work by space scientists had improved aviation safety.
That goes directly against the argument's central claim because it provides an Earth-based practical benefit.
Both options are related to the usefulness of space science.
Only one hits the exact weakness in the argument.
Common ways to strengthen an argument
After reviewing the questions, strong strengthening answers usually do one of several things.
1. Provide evidence that the proposed benefit really happens
If the argument says an activity improves a skill, evidence showing that improvement directly strengthens it.
For example:
Activity → improved concentration → better performance
Evidence supporting that middle connection is powerful.
2. Support the mechanism behind the argument
Why should A lead to B?
If the answer explains that connection, it often strengthens the argument substantially.
3. Remove an alternative explanation
Sometimes an argument compares two possible explanations.
If new evidence makes one alternative less likely, the remaining explanation becomes stronger.
This can be harder to recognise because the correct answer may not mention the preferred explanation directly.
4. Address the strongest objection
Suppose someone argues:
We should do X.
The obvious objection may be:
But X creates another problem.
If an option removes that problem, it strengthens the original recommendation.
This occurs frequently in the more difficult Selective questions.
Common ways to weaken an argument
Weakening answers often work in the opposite direction.
Look for an option that:
provides another explanation for the evidence
shows that the evidence does not apply to the conclusion
reveals a misleading comparison
provides an important counterexample
attacks a hidden assumption
shows that the claimed benefit or harm occurs for another reason
A good example from the Selective papers concerns old window glass. The argument uses old windows being thicker at the bottom as evidence that glass slowly flows over time. Evidence that much older glass objects do not show the same effect directly challenges the explanation being proposed.
That is much stronger than an option that merely provides another fact about glass.
A fast method students can use in the test
Under time pressure, students do not need to formally analyse every argument.
A practical five-step process works well:
1. Find the conclusion.
What does the speaker want me to believe?
2. Find the reason.
Why do they think the conclusion is true?
3. Check the question direction.
Am I strengthening or weakening?
4. Predict the type of answer before reading the options.
For strengthen: “I need evidence that this connection really works.”
For weaken: “I need a reason this conclusion might not follow.”
5. Compare the final two options by impact.
Which one changes my confidence in the conclusion the most?
This last step is especially important.
Do not ask:
“Which answer sounds good?”
Ask:
“Which answer changes the argument most?”
The “because test”
Another useful technique is to put the option into a simple sentence.
For strengthening:
“The conclusion is more convincing because ______.”
For weakening:
“The conclusion is less convincing because ______.”
If the sentence sounds awkward or requires several extra assumptions, the option is probably indirect.
The best answer often creates a very short, clear logical connection.
Pay attention to the strongest word in the argument
Words such as:
must, always, never, most effective, definitely, only, proves, impossible
make an argument easier to challenge.
For example, if someone says:
“This proves X.”
the correct weakening answer does not necessarily need to prove X false.
It only needs to show:
The evidence does not prove X.
Similarly, if a claim says something is the most effective solution, showing that it is useful is not enough. The supporting evidence should ideally justify the comparison with other solutions.
This distinction is one reason these questions can be difficult even for students with strong reading skills.
Do the options really follow a “two easy, two difficult” pattern?
Often, yes, approximately.
From the papers reviewed, students will frequently encounter:
an irrelevant option
an option that works in the wrong direction
a somewhat relevant option
the option that directly strengthens or weakens the key reasoning
But this should be treated as a useful observation, not a rule.
Sometimes three options are superficially plausible. Sometimes the best distractor is extremely close to the correct answer.
Instead of counting how many answers look wrong, students should focus on logical impact.
One final tip: separate “true” from “useful”
This is probably the most important mindset for these questions.
A statement can be:
completely true
interesting
relevant to the topic
and still be the wrong answer.
The question has already told the student to assume each option is true.
The only issue is:
What does this new fact do to the argument?
Students who learn to separate truth, relevance and logical impact usually find these questions much easier to manage.
Practising argument evaluation for OC and Selective Thinking Skills
Strengthen, weaken and support questions are not primarily tests of general knowledge. Students are being asked to understand an argument, identify the link between evidence and conclusion, and judge how new information changes that link.
That skill improves with targeted practice.
At Selective Journey, students can practise Thinking Skills questions alongside Mathematical Reasoning, Reading and Writing preparation.
For students preparing for the Selective High School Placement Test, explore our NSW Selective practice tests.
For younger students preparing for Opportunity Class placement, see our NSW OC practice tests.
You can also register for a free trial to explore the practice and review experience.