A writer arguing about hospital safety quotes a night nurse: "Most of the falls we see happen on the way to the bathroom between two and five in the morning." One version follows it with "Falls are a serious problem for older patients." Another follows it with "That timing points to the dark hallway, not the patient's balance: a two-dollar night-light could prevent an injury that often ends an older person's ability to live alone." Both use the same evidence, but only the second tells you what the quotation proves, and that sentence is where the argument happens.
Commentary names the link
Topic 1.3 covered finding claims, naming kinds of evidence, and telling quotation from paraphrase and summary. Commentary is the writer's own explanation of how a piece of evidence supports a claim. Evidence on its own is only a fact, a story, or a quotation. Commentary asserts a logical relationship between it and the claim, and that relationship has a shape you can name. Naming it is how you explain an argument, and how you test it.
| Relationship | What the commentary asserts | The question a skeptical reader asks |
|---|---|---|
| Example to pattern | This case stands for many like it | Is the case typical, or was it picked because it's unusual? |
| Sign to conclusion | This fact is a symptom of something larger | Could it be a sign of something else? |
| Cause to effect | This produced that | Could another cause explain the result? |
| Comparison | What held in that case will hold in this one | Do the cases share the feature that matters? |
| Principle applied | This case falls under a value the reader already holds | Does the reader accept the principle, and does the case really fit it? |
In the nurse example, the second version's commentary works by sign to conclusion (the hour is a symptom of darkness) and then cause to effect (light would prevent the fall). A reader can check both: if most falls happened in daylight, the commentary would collapse even though the quotation is accurate.
This is why reading for commentary matters more than reading for evidence. Writers rarely use false evidence; they often use true evidence with a weak link. A rise in bike-share trips is real evidence, and "so residents no longer want cars" is a link it can't hold, because more trips by bike is a sign of more biking and says nothing about how much anyone drives. When a question asks what a passage's evidence "supports" or what would "weaken" an argument, look at the link, not at the evidence.
How writers frame a source
When a writer brings in someone else's words or findings, the source arrives in a frame: a sentence or clause before it that says who is speaking and why their word counts, and commentary after it that says what the writer makes of it. Topic 1.3 showed how signal verbs ("finds," "insists") hint at a writer's stance. The full frame does more: it assigns the source a role in the line of reasoning.
- Authority: the source supports the writer's claim, and the frame stresses its credibility ("a structural engineer who has inspected the bridge every spring since 2015").
- Opponent: the source states the view the writer will answer, and the commentary after it turns ("That sounds reasonable until you look at...").
- Concession: the writer grants a source's point as true and then limits what it proves ("She is right about the cost. But cost was never the question.").
- Raw material: the writer takes a source's data and draws a different conclusion from it than the source did.
A strong frame also explains why this particular source matters. "Even the merchants' own parking study, which they paid for hoping to prove a shortage, found the garage never more than 60 percent full" frames the study as a reluctant witness: a source whose interests ran the other way, which makes its finding harder to dismiss. Writers choose frames like that on purpose, and questions asking what a reference "serves to" do are asking about the frame.
Arguments built from other arguments
Much of what you read on the exam is a writer working with other writers' arguments. To do that well, a writer considers another argument seriously, explains it accurately, and then fits it into the writer's own reasoning. That is synthesis, and the ways of fitting a source in are a small set of moves you can learn to recognize:
- Agree and extend: accept a source's claim and carry it further than the source did.
- Agree with a limit: accept the claim for some cases and show where it stops applying.
- Disagree with a reason: reject the claim and say what it gets wrong (bad evidence, a weak link, a missing case).
- Set sources against each other: use one source's evidence to answer another source's claim.
- Reconcile: show that two sources that seem to disagree are each right about a different part of the problem.
A writer who summarizes an opponent's case fairly, even generously, before departing from it gains your trust: it shows the writer understood the other side and still disagrees. Recognizing which move a writer makes is also what you will do with the six sources of the synthesis essay; Topic 3.4 covers writing with them.
Attribution: who said it, and why that matters to you
Attribution is the writer's acknowledgment of where words, ideas, data, and images came from: a signal phrase ("according to the county's 2023 water report"), a parenthetical citation, a footnote, a credit line under a photograph or chart. Paraphrased ideas need it as much as quotations do, because the idea is someone else's even when the wording is the writer's.
For you as a reader, attribution does three jobs. It lets you weigh the evidence: a crime statistic from a police department's annual report and the same number from an anonymous post deserve different trust, and you can only tell them apart if the writer says which it is. It keeps voices separate, so you can see where a source ends and the writer's commentary begins. And it is part of the writer's credibility: a writer who credits sources carefully, including the ones that cut against the argument, is showing you that the evidence can be checked. The reverse is a warning sign. "Studies show," "experts agree," and "it is well known" attribute a claim to no one, and a careful reader trusts them less.
Worked examples
The following paragraph is from an essay arguing that a city art museum should drop its $18 admission fee.
On the first Sunday of every month, when admission is free, the museum's attendance roughly triples. The more telling number is on the sign-in cards: on free Sundays, visitors list nearly twice as many different home zip codes as on paid days. The fee is not simply trimming the crowd; it is sorting it, letting in the neighborhoods that can pay and keeping out the ones that can't. A public museum that admits the city by income has stopped being public in any sense that matters.
Identify the claim, the evidence, and the commentary, name the logical relationship the commentary asserts, and say what a skeptical reader could question.
Show solution
Claim. The last sentence: a museum that admits people by income has stopped being public, so (by implication) the fee should go.
Evidence. Two observations: attendance triples on free Sundays, and visitors on those days come from nearly twice as many zip codes.
Commentary. "The fee is not simply trimming the crowd; it is sorting it." This sentence tells you what the zip-code count means. The writer treats the wider spread of neighborhoods as a sign that the fee excludes particular places, and then applies a principle the readers presumably hold, that a public institution should not admit people by income.
What a skeptic could question. The sign-to-conclusion link has a rival explanation. Free Sundays may draw visitors from far away for reasons other than price: they may be advertised more widely, or scheduled with special events. If so, the zip codes are a sign of publicity, not exclusion. The writer would strengthen the link by showing that the extra zip codes are lower-income neighborhoods, or that free days without special events show the same spread.
Why this is the move. Naming the relationship tells you exactly where the argument is vulnerable. Questions that ask which finding would "most weaken" an argument are looking for the rival explanation of the link, not a challenge to the facts.
Each passage below quotes the same invented traffic engineer, Dana Ortiz: "Narrower lanes slow drivers more reliably than lower speed-limit signs do." For each, identify the role the frame gives the source.
(A) The fix for Harbor Road is paint, not signs. Dana Ortiz, who has redesigned more than forty streets for the state transportation department, puts it plainly: "Narrower lanes slow drivers more reliably than lower speed-limit signs do." Repainting Harbor Road's lanes from twelve feet to ten would cost less than a single new traffic light.
(B) Traffic consultants like Dana Ortiz assure us that "narrower lanes slow drivers more reliably than lower speed-limit signs do." Perhaps on a quiet side street. Harbor Road carries the fire engines from Station 3, and a ten-foot lane leaves an engine eight and a half feet wide nine inches of clearance on each side.
(C) Dana Ortiz is right that "narrower lanes slow drivers more reliably than lower speed-limit signs do." But repainting Harbor Road must wait for repaving, scheduled for 2029, and children walk to Bay Street School this fall. A speed camera can be installed in a month.
Show solution
(A) Authority. The frame before the quotation builds credibility (forty streets, a state agency), and the commentary after it applies her point directly to the writer's proposal. The source supports the claim.
(B) Opponent. "Assure us" keeps the source at arm's length, and the commentary immediately limits it ("Perhaps on a quiet side street") and answers it with a case where her rule fails. The quotation is there to be rebutted.
(C) Concession. The writer grants the point fully ("is right") and then argues that it doesn't decide this question, because timing matters more than effectiveness. The source is accepted and set aside.
Why this matters. The quotation is identical in all three. Its role comes entirely from the frame, which is why a question about what a reference "serves to" do can't be answered from the quotation alone. Read the sentence before it and the sentence after it.
The following passage is excerpted from a column in a small-town newspaper. It responds to two earlier columns about a proposal to move the town's Saturday farmers market from the town square to the county fairground, two miles away.
Ruth Okafor, who has managed the farmers market for nine years, makes the best case for the fairground I have read. The square holds thirty-one stalls; the fairground lot would hold seventy, with parking for four hundred cars instead of the sixty spaces around the square. Her waiting list of vendors is longer than the market itself. Anyone who has circled the square three times on a Saturday morning knows she is not inventing the problem.
But a market is more than stalls and parking. Last week Glen Marsh, who owns the hardware store on the north side of the square, wrote in these pages that his Saturday sales run double his Wednesday sales, and he worried about what the move would do to his store. He is right to worry, and numbers he did not mention make his case stronger. I asked four other shops on the square to count their Saturday receipts stamped before noon, while the market runs. Three of the four did more than half their Saturday business in those four hours.
Those figures cut in both directions. The shops need the market's crowd, but the crowd is also there because of the shops: people who come for tomatoes stay for coffee, a key cut, a birthday card. A market on an open lot two miles from anything sells vegetables. A market on the square is a Saturday morning in town, which is why people come. Ms. Okafor's seventy stalls might end up selling to fewer shoppers than her thirty-one do now.
The answer to her waiting list is to close the two side streets off the square on Saturday mornings, which would make room for twenty more stalls without moving any of them.
Question 1. In the first paragraph, the writer's account of Okafor's argument primarily serves to
- (A) show that the writer agrees the market should move to the fairground
- (B) present the opposing case fairly and grant the problem it identifies before disputing its solution
- (C) criticize Okafor for exaggerating the shortage of parking
- (D) establish Okafor as the writer's main source of evidence about the shops on the square
Question 2. The writer's use of Glen Marsh's column is best described as
- (A) dismissing Marsh's argument because he has a financial interest in the outcome
- (B) accepting Marsh's concern and adding evidence that supports a broader conclusion than Marsh drew
- (C) summarizing Marsh's column without adding to it
- (D) using Marsh's sales figures to support Okafor's proposal
Question 3. The sentence "Those figures cut in both directions" (third paragraph) signals that the writer will
- (A) argue that the receipt counts are unreliable
- (B) concede that the move to the fairground would help the shops
- (C) interpret the receipt counts as evidence that the market and the shops depend on each other
- (D) present a second set of figures that contradicts the first
Show solution
1. (B). The writer calls Okafor's case "the best case for the fairground I have read," gives her numbers accurately, and confirms the problem from experience ("she is not inventing the problem"). That is a concession: the shortage is real. Paragraph 2 then opens with "But," and the last paragraph rejects her solution. (A) mistakes the concession for agreement with her conclusion, which the rest of the column rejects. (C) contradicts the paragraph, and (D) confuses her with Marsh: Okafor's numbers are about stalls and parking, not shops.
2. (B). The writer says Marsh "is right to worry" (accepting his concern), then adds the receipt counts from four other shops (new evidence), and draws a conclusion Marsh didn't: that the market itself depends on the square and would lose shoppers at the fairground. That is agree and extend. (A) is a reason a writer could give, but this one never questions Marsh's motives. (C) ignores the new evidence, and (D) reverses the argument.
3. (C). The question asks what the writer does next, and the next sentence says what the two directions are: the shops need the market, and the market's crowd comes partly because of the shops. That is commentary assigning a two-way relationship to the evidence, which is what (C) describes. (A) and (D) are wrong because the writer neither doubts the counts nor adds new figures, and (B) reverses the column's position. Whether the writer's interpretation holds is a separate question, and a sharp reader notices a problem: the receipt counts support only the first direction (the shops' business depends on market hours). The second direction (people come to the market because of the shops) rests on an illustration, the shopper who stays for coffee, not on any count. Questions asking what would strengthen this argument would point to that gap: evidence that market shoppers also visit the shops.
The method behind all three. Each question asked how the writer uses a source or a set of figures, never what the source says. Find the frame (praise, "right to worry," "cut in both directions") and the commentary after it, and the role follows.
Where students lose points
On the exam
Multiple-choice reading questions on this skill ask what a reference to a source or a set of figures primarily serves to do, how a writer uses another writer's argument, what a piece of evidence supports, and which new information would strengthen or weaken an argument. Passages that respond to other writers, quoting or summarizing them, are a natural home for these questions. The synthesis essay asks you to read six sources this way before you write: what each one claims, how good its link is, and how it bears on the others. Topic 3.4 covers integrating them into your own argument, and Topic 3.5 covers the line of reasoning that commentary builds across a whole text.
Check yourself
Question 1
A writer argues: "In the year since the public library began staying open until 9 p.m., the number of students failing a class at the high school has dropped by a fifth. The late hours are clearly raising grades." Which of the following findings, if true, would most weaken the link between the evidence and the claim?
- A
The library counts its evening visitors at the door each night.
- B
That same year, the high school began letting students retake any failed test once.
- C
Several students told a reporter they like the quiet of the library at night.
- D
The library plans to extend its weekend hours next year.
Show answer
B
The commentary asserts cause to effect, and a retake policy introduced the same year is a rival cause that could explain the drop by itself. Choice C is tempting because it is about students using the library, but it supports the writer rather than weakening the link.
- A
Question 2
A student arguing that her school should replace its bottled-water vending machines with free refill stations writes: "Even the survey the vending company paid for, hoping to show strong demand for bottled water, found that most students would rather refill their own bottle for free." What role does this frame give the survey, and why does the frame make the evidence stronger?
Show answer
The frame makes the survey a reluctant witness: a source whose sponsor wanted the opposite result. Because the vending company had every reason to find demand for its product, a finding that students prefer free refills is hard to dismiss as biased toward the student's side.
A frame tells the reader how to weigh a source. Pointing out that a source's interests ran against its own finding turns a possible objection (who paid for it) into added strength.
Question 3
A writer says: "Hollis is right that homework in the early grades shows little benefit, but her conclusion that all homework should be abolished ignores the high school results in her own study, where students who did homework scored higher." Which best describes how the writer uses Hollis's argument?
- A
Accepts it fully and extends it to high school
- B
Rejects it because Hollis's study is unreliable
- C
Accepts part of it and uses Hollis's own evidence to limit her conclusion
- D
Summarizes it without taking a position
Show answer
C
The writer grants the early-grades point and then shows that Hollis's own high school data stops her conclusion from applying to all students, which is agreeing with a limit. Choice B is tempting because the writer disagrees, but the writer relies on Hollis's study rather than attacking it.
- A
Question 4
An editorial states: "Studies show that teenagers who eat breakfast earn higher grades." It gives no further attribution. Why should a careful reader trust this claim less, and name two things proper attribution would let the reader check.
Show answer
"Studies show" credits the claim to no one, so the reader can't judge how good the evidence is. Proper attribution would let the reader check who did the research and whether they have a stake in the result, and how it was done, for example how many students were studied and whether the study only found that breakfast and grades go together rather than that breakfast causes higher grades.
Attribution lets a reader weigh evidence. A claim credited to unnamed studies can't be weighed or checked, which is why a writer who names sources earns more trust.