Year 13 · English · Literacy
Evaluating arguments and reasoning
Evaluate the strength of arguments by examining evidence and reasoning, and identify common logical fallacies in persuasive texts.
Awaiting educator review. This material was drafted by our content team with AI assistance and is waiting for review by a qualified educator. Please check it suits your child before using it. Created 10 October 2026.
These lessons were written around Australian Curriculum strands and matched to New Zealand year levels by age (NZ Year 1 is the first year of school). They are not yet mapped to The New Zealand Curriculum, so check them against your own learning programme.
Learning goals
Learners will
- Evaluate whether evidence in an argument is relevant, sufficient and reliable.
- Identify common logical fallacies and explain why they weaken an argument.
Success looks like
- I can judge whether evidence actually supports a claim.
- I can name and explain at least five logical fallacies.
- I can avoid fallacies in my own persuasive writing.
The big idea
Senior English asks you not only to identify persuasive techniques but to evaluate arguments: how well does the reasoning actually hold up?
Test the evidence. Is it relevant (does it relate to the claim)? Sufficient (is there enough)? Reliable (where did it come from, and is it current)? A single anecdote about one person, for instance, is insufficient to prove a claim about an entire population.
A logical fallacy is a reasoning error. Fallacies can be persuasive, which is exactly why they are worth recognising:
- Ad hominem: 'Why listen to her views on housing? She can't even keep her own garden tidy.'
- Straw man: 'My opponent wants cyclists to have safer lanes – so he wants to ban cars entirely!'
- False dilemma: 'Either we build the freeway or the city dies.' Slippery slope: 'If we allow phones at lunch, soon nobody will ever talk face-to-face again.'
- Bandwagon: 'Everyone is switching to this plan – you should too.' Hasty generalisation: 'My two cousins hated the new course, so it must be terrible.'
When writing about fallacies, explain why the reasoning fails: for example, 'This is a false dilemma because it ignores alternatives such as improved public transport.' In your own arguments, avoid fallacies – a well-informed audience will notice them and trust you less.
Worked examples
Identifying and explaining a fallacy
Original letter extract: 'The councillor says we should reduce speed limits near schools. But this is the same councillor who was fined for parking illegally last year. Clearly his ideas can't be trusted.' Identify and explain the fallacy.
- Find the claim being attacked: reducing school-zone speed limits.
- Notice the response does not address the claim's merits.
- It attacks the councillor's personal behaviour instead.
- Name the fallacy: ad hominem.
Answer: This is an ad hominem fallacy: rather than evaluating whether lower speed limits would improve safety, the writer attacks the councillor's parking record, which is irrelevant to the merits of the proposal.
Evaluating evidence
Original claim: 'Homeschooled children are happier than school students. My neighbour's son is homeschooled and he's always cheerful.' Evaluate the evidence.
- Relevance: the neighbour's son relates to the topic, so it is relevant.
- Sufficiency: one child cannot represent all homeschooled children – insufficient.
- Reliability: a casual observation, not systematic research.
- Name the flaw: hasty generalisation.
Answer: The evidence is relevant but insufficient and unreliable: one cheerful child cannot support a claim about all homeschooled children, making this a hasty generalisation.
Practice check
Have a go, then check your answers. Each answer comes with an explanation.
Answer guide for parents
'You're either with us or against us.' Which fallacy is this?
False dilemma — It presents only two options when others exist.
'If we let students redo one test, next they'll want to redo every subject, and soon grades will mean nothing.' Which fallacy?
Slippery slope — It claims an extreme chain of consequences without evidence.
'Millions of Australians already use this app, so it must be the best.' Which fallacy?
Bandwagon — Popularity is presented as proof of quality.
Which question tests whether evidence is sufficient?
Is there enough evidence to support the size of the claim? — Sufficiency is about whether the amount of evidence matches the claim.
'My opponent wants to review the school uniform policy – she clearly wants students to wear pyjamas to class!' Which fallacy?
Straw man — The opponent's reasonable position is distorted into an absurd one.
Which fallacy attacks the person instead of their argument? (two words)
Ad hominem — Ad hominem is Latin for 'to the person'.
Drawing a broad conclusion from too few examples is a ______ generalisation. (one word)
Hasty — A hasty generalisation relies on insufficient evidence.
What is the general term for a flaw in reasoning? A logical ______. (one word)
Fallacy — Logical fallacies make arguments seem stronger than they are.
Watch out for
- Believing that an argument containing a fallacy must have a false conclusion. The conclusion may still be true; the reasoning offered just does not prove it.
- Labelling any criticism of a person as ad hominem. Questioning a source's relevant expertise or conflict of interest can be legitimate.
- Thinking fallacy-spotting is the whole evaluation. Strong evaluation also weighs the quality of evidence and the overall logic.
Tips for parents
- Play 'spot the fallacy' with advertisements, political debates or online comments – keep it light and even-handed.
- Model good reasoning in family discussions by asking, 'What's the evidence for that?'
- Encourage your learner to check their own persuasive drafts for fallacies before submitting.
Go further
- Write a deliberately flawed 150-word opinion piece containing four fallacies, then swap with someone to identify them.
- Evaluate a published opinion article: rate its evidence for relevance, sufficiency and reliability and justify each rating.
- Rewrite a fallacious argument so the same contention is supported by sound reasoning.