Short on time? This page is the recap. For explanations and worked examples, use the full study guide.
Recap
- When using sources, the strongest arguments recognise and acknowledge biases and limitations and account for them in their reasoning.
- The degree to which a source considers other positions reflects its degree of bias.
- In reading, identify and explain claims and evidence. In writing, develop a paragraph with a claim and evidence.
Key relationships
| Sign of bias | Check |
|---|---|
| Vested interest | Who benefits? |
| Loaded language | Are the words emotive or measured? |
| Omission | Are other positions mentioned fairly? |
| Selective evidence | Is contrary evidence missing? |
| Hidden method | Is the source of data stated? |
| Limitation | Check |
|---|---|
| Sample size | How many? |
| Selection | Who was chosen and how? |
| Scope | Where and when? |
| Date | How recent? |
| Method | How measured? |
| Type | Anecdote, opinion, data? |
| Way to account for it | Language |
|---|---|
| Qualify | “suggests”, “in this case” |
| Name it | “Although the sample was small…” |
| Add evidence | “A second source, independent of the company, shows…” |
Assumptions and conventions
- Judge each claim on its evidence, not only the source’s label.
- Name the source’s interest when it matters.
- Do not call a source “biased” without saying how.
- A biased source can still show what a group claims or believes.
Mistakes to avoid
- Treating a company’s brochure as neutral evidence.
- Calling every source biased without evidence.
- Ignoring sample size or selection.
- Overclaiming from a small survey.
- Dismissing a source entirely because of bias.
- Acknowledging a limitation but not adjusting the claim.
- Judging by tone alone.
Worked mini-example
Source: “In a survey of 50 visitors to our stand, 9 in 10 said our filter water tasted better.”
Interest: the company sells filters. Limitations: 50 people; chosen from the company’s own stand; taste, not safety.
Responsible use: “A filter company reports that 45 of 50 visitors to its stand preferred its water, but the sample is small and self-selected, so the figure says little about tap water in general.”
On the exam
When you use a source, say what it can show and what it cannot. When a reading question asks about bias, use the measure of how fully the source considers other positions.
Sentence frames for use in writing
- “Although the survey was small, it suggests ….”
- “As a company that sells …, the author has an interest in …, so the claim should be read with care.”
- “The report does not consider …, which limits what it can show about ….”
- “A second source, independent of …, supports the claim by ….”
These frames name the limitation and then adjust the claim, which is how bias and limits are accounted for.
Quick self-check
- What does the degree of consideration of other positions show? (How biased the source is.)
- Name two limitations of “9 in 10 of 50 visitors to our stand preferred it”. (Small sample; self-selected group; measured taste, not safety.)
- How can you account for a limitation? (Qualify the claim, name the limitation, add other evidence.)
Next: practice questions.