Grade 8 · Evaluating Sources · Source Quality
Evaluating Evidence and Faulty Reasoning
Test evidence for relevance and sufficiency.
Learning objectives
- Test evidence for relevance and sufficiency
- Name three common reasoning errors
- Judge whether a claim is supported
AERO English Language Arts alignment
AERO.ELA.8.RI.8
Trace and evaluate the argument and specific claims in a text, distinguishing claims supported by sound reasoning and relevant evidence from those that are not. Grade 8 / MYP 3 emphasis: handle subtler techniques such as irony, bias and conflicting evidence, and justify interpretations.
AERO.ELA.8.RI.6
Determine an author's purpose and point of view, and analyse how the author acknowledges or responds to conflicting evidence or viewpoints. Grade 8 / MYP 3 emphasis: handle subtler techniques such as irony, bias and conflicting evidence, and justify interpretations.
AERO.ELA.8.RI.1
Cite textual evidence to support analysis of what an informational text states explicitly and of inferences drawn from it. Grade 8 / MYP 3 emphasis: handle subtler techniques such as irony, bias and conflicting evidence, and justify interpretations.
AERO.ELA.8.RI.2
Determine a central idea of an informational text and analyse its development across the text; provide an objective summary. Grade 8 / MYP 3 emphasis: handle subtler techniques such as irony, bias and conflicting evidence, and justify interpretations.
AERO.ELA.8.RI.4
Determine the meaning of words and phrases as used in an informational text, including technical, connotative and figurative meanings. Grade 8 / MYP 3 emphasis: handle subtler techniques such as irony, bias and conflicting evidence, and justify interpretations.
MYP criteria
- Criterion A — Analysing
- Criterion B — Organizing
ENGAGE
Would You Believe This Claim?
Imagine that a student says, “Everyone at Education City wants longer break times because three of my friends said so.” The friends’ opinions relate to the claim, but are they enough to represent every student? Strong arguments need evidence that is both relevant and sufficient. They also need sound reasoning. In this lesson, you will investigate a proposal about facilities on Doha Corniche, identify faulty reasoning and decide which conclusions the evidence can genuinely support.
Think about it
- Can evidence be relevant but still too limited?
- What makes a conclusion trustworthy?
EXPLORE
Read Closely: A Proposal for the Corniche
More Refill Stations, Better Visits
Doha Corniche needs more shaded water-refill stations. In a survey conducted beside one busy station on a warm Tuesday between midday and 2 p.m., 84 of 120 visitors reported waiting more than three minutes. A volunteer also saw one family leave the queue. These findings prove that all refill stations are always overcrowded. Last week, one station stopped working after a particularly hot afternoon. The hot weather must have caused the fault, so every unshaded station will soon break. The city must add shaded stations immediately, or visitors will stop using the Corniche altogether.
The facilities team offers conflicting evidence. Its records show that seven of ten stations passed every maintenance inspection last month. Staff also measured average queues of under one minute at six locations between 7 and 9 a.m. However, morning visitors clearly do not need water as much, so those figures can be ignored. Only someone who enjoys carrying an empty bottle would oppose the proposal. Despite this unfair remark, the midday survey identifies a possible problem at a busy time. A sensible next step would be a one-month pilot of extra shade at two stations, followed by queue measurements at several locations and times.
Original extract
This text was written for this lesson. Notice that it contains useful evidence, conflicting evidence and deliberate reasoning errors.
Think about it
- Which evidence is relevant to the claim about overcrowding?
- Why is the midday survey not sufficient to describe every station?
- How does the writer respond to the facilities team’s conflicting evidence?
EXPLAIN
How to Test an Argument
An argument connects a claim, evidence and reasoning. The claim is what the writer wants you to accept. Evidence supplies facts, examples, observations or data. Reasoning explains why that evidence supports the claim. You must test all three parts rather than accepting a confident conclusion.
| Test | Question to ask | Application to the extract |
|---|---|---|
| Relevance | Does the evidence directly relate to the claim? | Queue times relate directly to overcrowding. |
| Sufficiency | Is there enough varied evidence for the size of the claim? | One place and one time period cannot represent every station. |
| Credibility | How was the evidence collected, and can it be checked? | The survey gives numbers and conditions, but its sample is limited. |
| Reasoning | Does the conclusion follow logically from the evidence? | A crowded station does not prove that all stations are always crowded. |
Three Common Reasoning Errors
- Hasty generalisation: reaching a broad conclusion from too few or unrepresentative examples. The extract moves from one busy station to all stations.
- False cause: assuming that one event caused another without enough proof. The station failed after a hot afternoon, but timing alone does not prove that heat caused the fault.
- False dilemma, or either-or reasoning: presenting only two choices when other possibilities exist. Adding stations immediately or losing all visitors are not the only options.
Irony is not evidence
The comment about enjoying an empty bottle is ironic because it suggests that every opponent wants inconvenience. It may influence feelings, but it supplies no evidence and reveals the writer’s bias.
A fair writer acknowledges conflicting evidence and responds to it accurately. In the extract, the facilities team’s morning data has limits, but the writer dismisses it without careful analysis. A stronger response would compare morning and midday conditions, recognise that both sets of data are incomplete, and request measurements across more times and locations.
A justified judgement
State how far the claim is supported, then explain why. Here, the evidence supports investigating midday queues at one busy location. It does not support claims about every station, future breakdowns or all visitors. The limited pilot is therefore more reasonable than the original demand.
MYP_PRACTICE
Conduct an Evidence Audit
Audit the Corniche proposal as if you were advising a facilities committee. Separate the claim, evidence and reasoning. Then test each piece of evidence for relevance and sufficiency, identify the three reasoning errors, and write an organised judgement explaining exactly how far the main claim is supported.
- Write the main claim in one clear sentence.
- List the midday survey, volunteer observation, maintenance record and morning queue data.
- Mark each piece of evidence as relevant or irrelevant, then judge whether it is sufficient.
- Find one hasty generalisation, one false cause and one false dilemma.
- Write a four-sentence judgement: decision, strongest evidence, limitation and sensible next step.
EXIT_TICKET
Before you close this lesson
Think about it
- How can evidence be relevant without being sufficient?
- Which reasoning error are you now most confident about identifying, and why?
Watch
How to Argue - Philosophical Reasoning: Crash Course Philosophy #2
CrashCourse · 10 min
Learn how premises, conclusions, validity, and sound reasoning form a strong argument.
Before you watch: How is a reasoned argument different from a quarrel?
- What roles do premises and conclusions play in an argument?
- How can you test whether a conclusion follows logically from its premises?
Watch
Check Yourself with Lateral Reading: Crash Course Navigating Digital Information #3
CrashCourse · 14 min
Learn to investigate online claims by leaving a page and checking what reliable external sources say about it.
Before you watch: Why might studying only one webpage give you an incomplete picture?
- What is lateral reading, and how is it different from reading vertically?
- Which outside sources would you consult to verify an unfamiliar website?
Interactive practice · evidence reasoning audit
Build a Supported Verdict
Use the extract to complete an evidence audit and produce a concise committee recommendation. Your verdict must distinguish useful evidence from unsupported reasoning and acknowledge the conflicting viewpoint.
Rows to complete
Text
Main claim: Doha Corniche needs more shaded water-refill stations.
Check your answer
Task
Imagine that your recommendation will help a committee decide whether further investigation is needed.
Sentence frames
Labels you can use
Your answer
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Key vocabulary
- relevance
- How directly evidence connects to the claim being examined.
- sufficiency
- Whether there is enough evidence to justify a conclusion.
- hasty generalisation
- A broad conclusion based on too few or unrepresentative examples.
- false cause
- Assuming one event caused another without enough proof.
Practice questions
0/3 correct
Level 1 · Criterion A
Which evidence is most relevant to the claim that visitors experience long queues at midday?
Level 2 · Criterion A
The writer says that hot weather caused a station fault because the fault happened after a hot afternoon. Which error is this?
Level 2 · Criterion B
Which order would create the clearest organised judgement of the proposal?
MYP criterion tasks
Level 3 · Criterion A
Analyse how the writer responds to the facilities team’s conflicting evidence. What does the response reveal about the writer’s perspective?
Level 3 · Criterion B
Write an organised judgement explaining how far the claim that the Corniche needs more shaded refill stations is supported.
Reflect & track
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