In Composition you checked whether a source is credible and practiced qualifying claims. Weighing evidence asks a further question: how well does this piece of evidence support this claim?
| Test | Ask | Fails when |
|---|---|---|
| Relevant | Does it bear on this claim? | a fact about bus costs offered to show students are tired |
| Sufficient | Is there enough of it? | one friend’s story offered as proof about all teenagers |
| Accurate | Is it correct and from a reliable source? | a number with no source, or one copied wrong |
| Current | Is it recent enough, when timing matters? | a 1998 survey of phone use |
| Fairly represented | Does it say what the source said, in context? | a quotation cut so it means the opposite |
Key idea
Weigh evidence; don’t just count it. One relevant, accurate, well-sampled study outweighs five stories that miss the point.
Why it works
Readers judge your claim by its weakest support. A single outdated number or a quotation taken out of context makes a careful reader doubt everything else, and it hands your opponents an easy reply.
Worked example: Which is stronger?
Claim: the school should add a second late bus. Evidence A: “My friend missed the late bus twice last month.” Evidence B: “The transportation office’s sign-in sheets show 30 to 40 students turned away from the full late bus each week this fall.”
- Both are relevant: they are about the late bus being too full.
- A is one case, told secondhand: not sufficient to show a pattern.
- B is a count from records, recent and covering many weeks: sufficient and accurate.
- A can still help as an example that puts a face on B’s numbers.
Answer: B is stronger evidence; A works best as an illustration of B.
Worked example: Fairly represented?
A review said: “The new park is beautiful, but the parking lot is far too small.” An ad for the park quotes the review as saying: “The new park is beautiful.” Is that fair?
- The quotation is accurate word for word.
- But it leaves out the reviewer’s main complaint, the parking lot.
- If the ad suggests the reviewer simply praised the park, it misrepresents the source. Fair use would keep the reviewer’s point clear.
Answer: Accurate words, but not fairly represented if it hides the reviewer’s complaint.
Common mistake
Counting pieces of evidence instead of weighing them. Five quotations that all repeat one weak survey are still one weak survey. Check each piece with the five tests, and lead with your strongest.