An essay arguing that a town should save its old movie theater gives three pieces of support: the theater sold 41,000 tickets last year, the writer's parents had their first date in its balcony, and the building was designed by the same architect as the state capitol. All three are evidence, and each does a different job. The ticket count shows the theater is still used, the first date makes readers feel what would be lost, and the architect ties a small-town building to something the whole state is proud of.
What a piece of evidence is doing
Evidence never sits in an argument by itself. It is there to do something to a claim: make it visible, make it understandable, make it feel larger, or attach it to something else. Six functions cover most of what you will see. Here they are, each shown in an essay arguing that a city should require new parking lots to plant shade trees.
| Function | What the evidence does | Example in the parking-lot essay |
|---|---|---|
| Illustrate | Turns a general claim into a concrete case the reader can picture | The asphalt in the Fairview Mall lot measured 151°F on an August afternoon |
| Clarify | Makes an abstract or technical idea understandable, often by comparison | A paved lot stores heat the way a cast-iron pan does, giving it back long after the sun goes down |
| Set a mood | Creates the feeling the writer wants the reader in, often at the start | A cashier waiting at a bus stop in the middle of the lot, with no shade in any direction |
| Exemplify | Offers one case as typical of a whole group | The Fairview lot, one of forty treeless lots built since 2000, all designed to the same code |
| Associate | Links the subject to something else so the reader's feelings about that thing transfer | The same code once required lots to plant trees, until a 1990s rule change dropped the requirement to cut costs |
| Amplify | Enlarges the point, making it seem bigger or more urgent | Together the treeless lots cover more ground than the city's parks |
The labels overlap, and one piece of evidence often does two jobs. The bus-stop scene sets a mood and also illustrates the heat. What matters on the exam is not choosing the perfect label. It is stating, specifically, what the evidence does for which claim. "The writer includes the bus-stop scene to make readers feel the heat as a person stranded in it would, before giving them a single number" is an explanation. "The writer uses an anecdote" only names a type.
Illustrate or exemplify? Both use a single case. When a writer illustrates, the case makes a claim visible: you see the heat. When a writer exemplifies, the case stands in for a category: this lot is one of forty like it. If the passage says or implies "and there are many more like this," the case is exemplifying.
Associate is the subtlest function and the easiest to miss. The writer puts the subject next to something the audience already has feelings about, a historical event, a respected person, a familiar wrong, and lets those feelings carry over. When a question asks what a reference to a past event "serves to" do, check whether the writer is borrowing the audience's feelings about that event.
Why writers choose the evidence they do
A writer rarely has only one piece of evidence available, so the evidence on the page was selected. Strategic selection pays off in three ways, and you can ask about each when you read.
It makes the reasoning stronger. The evidence bears directly on the claim, comes from a source the audience trusts, and is representative instead of a freak case. A writer who wants a parking-lot rule changed will quote the city's own temperature survey before an activist group's, because the council can't dismiss its own numbers.
It reaches the audience's emotions and values. Topic 2.1 showed that audiences respond to what they already care about. A writer addressing small-business owners picks the shopper who drove past a sweltering lot to a shaded one; a writer addressing a health board picks the heat-stroke admissions.
It makes the writer more credible. Specific, well-sourced evidence shows the writer did the work. Firsthand evidence shows the writer was there. Evidence that concedes something, such as an admission that trees cost money to maintain, shows the writer is being fair.
So when an exam question asks why a writer chose a particular piece of evidence, the answer usually lies in one of those three payoffs, read against the audience: "The writer cites the city's own survey so that council members can't dismiss the figures as an outsider's."
When evidence is enough
Evidence is sufficient when there is enough of it, and it is good enough, to support the claim it is attached to. Both halves matter, and both depend on how large the claim is.
- Quantity has to match the claim's reach. One anecdote can illustrate a claim, but it can't establish a general pattern. "Teenagers are reading less than they used to" needs evidence across many teenagers and many years; "my brother hasn't finished a book since August" is a case, not a trend.
- Quality means the evidence is relevant (it bears on this claim, not a nearby one), credible (its source is in a position to know), specific (names, numbers, dates, places), and representative (typical, not an outlier chosen because it is dramatic).
The practical test is to ask what claim the evidence actually proves and compare it with the claim the writer makes. When the claim is bigger than the evidence, the argument is weak at that point. Writers sometimes slip a sweeping claim into a paragraph that is otherwise well supported, and a reader who checks each claim against its evidence catches it. Multiple-choice questions ask about this directly: which claim is least supported, which addition would most strengthen a point, which statement goes beyond what the writer has shown.
The thesis: the claim the whole argument defends
An argument makes many claims. One of them is the thesis: the main claim, the one every other claim and every piece of evidence is there to support. A paragraph's claim is a step; the thesis is where the steps lead.
A thesis is not always a single sentence, and it is not always stated. When the writer states it directly, you have a thesis statement, often at the end of the introduction. But writers also hold the thesis back until the conclusion (a common choice with an audience likely to resist it, who might stop reading if they met it first), split it across two or three sentences, or never state it at all and let the evidence and claims make it for them. A thesis that is never stated is still there. You find it by reasoning from the parts:
- Write down the claim each paragraph or section makes, in a few words.
- Ask what single claim all of them support. That is the thesis.
- Check it against the ending and the title. Writers usually point toward the thesis in both.
- Make sure it is a claim, something a reasonable person could dispute, and not the topic. "Repair shops" is a topic. "Repair shops are disappearing" is a fact. "A town that stops repairing things loses skills it can't buy back" is a thesis.
A stated thesis often tells you how the argument is built. "The library should open on Sundays because working families have no other day to use it, students need a quiet place to study before Monday's tests, and the cost is smaller than the board claims" announces three reasons, and you should expect the essay to take them in that order. A thesis that begins "Although the plan will cost more at first" signals that the writer will deal with cost before turning to the benefits. Reading the thesis for structure gives you a map of the passage, which helps on questions about the function of a paragraph.
Worked examples
A resident wrote this paragraph in a letter to a city council.
At four o'clock on a July afternoon last summer, the thermometer outside the laundromat on Dalton Street read 104 degrees. Six blocks north, under the old oaks of Prospect Avenue, it read 93. A street tree works like an awning that sweats: its canopy blocks the sun, and the water evaporating from its leaves draws heat out of the air around it. Dalton Street is typical of the east side, where the city's own tree survey counted one street tree for every nine houses. The survey found a gap of ten degrees or more between fourteen east-side blocks and the shaded streets nearby, and every one of those blocks is in a neighborhood that the 1958 expressway cut off from the river parks. Dalton Street does not need another study. It needs shade before next July.
Explain what each piece of evidence does for the writer's claim that Dalton Street needs trees now.
Show solution
- The laundromat thermometer at four o'clock sets a mood (an ordinary place in the worst heat of the day) and illustrates the claim with two concrete readings eleven degrees apart. The council sees the difference before being told what causes it.
- "An awning that sweats" clarifies how trees cool a street, explaining shade and evaporation through a familiar object so that a non-scientist accepts the mechanism.
- "Typical of the east side," one tree per nine houses exemplifies: Dalton Street is presented as one case of a whole district.
- Fourteen blocks with the same gap amplifies: the problem is a pattern across a part of the city, not one unlucky street.
- The 1958 expressway associates today's heat with an old decision that divided neighborhoods. Council members who see that decision as a past wrong now see the missing trees as part of it, and as something the city owes.
Why this selection is strategic. The temperatures are measurements, which strengthens the reasoning. The expressway reaches the council's sense of fairness. And the figures come from "the city's own tree survey," which makes the writer credible: the council can't call its own numbers biased. Notice also that the evidence is sufficient for the claim the writer makes. Fourteen blocks support "the east side lacks shade"; a single thermometer reading would not have.
This is the whole of a short essay a student wrote for a school magazine.
Mr. Halvorsen's shop on Larch Street has no sign, only a hand-lettered card in the window: RADIOS, LAMPS, CLOCKS. Last spring I brought him a clock radio that had belonged to my grandmother, and he opened it on the counter while I watched. "Capacitor," he said, holding up a part smaller than a pencil eraser. It cost forty cents. The repair took him eleven minutes, and he spent another twenty explaining what a capacitor does, because I asked.
The big-box store on Route 4 had offered me a coupon toward a new clock radio. The new one would have cost fourteen dollars, and the old one would have gone in the trash with its forty-cent problem still inside it.
Mr. Halvorsen is seventy-eight. He has no apprentice. When I asked who would fix the town's radios after him, he laughed and said nobody would need to, because by then everyone would just buy new ones. He did not sound as if he thought that was progress.
Write a thesis statement for the essay, and explain why it is better than the three candidates below.
- (1) Mr. Halvorsen is a skilled and generous repairman.
- (2) This essay is about repairing things instead of replacing them.
- (3) Modern technology is ruining society.
Show solution
Step 1: the claim of each paragraph. Paragraph 1: a repair cost forty cents and eleven minutes, and came with knowledge the writer couldn't get elsewhere. Paragraph 2: replacement was cheap but wasteful, and it would have thrown away a small, fixable problem. Paragraph 3: when Mr. Halvorsen retires, his skill goes with him, and he sees that as a loss.
Step 2: what they all support.
When a town replaces things instead of repairing them, it throws away more than broken objects: it lets disappear the skill and knowledge that repair kept alive, and that loss can't be bought back for fourteen dollars.
Why this works. It is a claim a reader could dispute (someone could argue cheap replacement is simply efficient), and every paragraph supports a part of it. The forty-cent part and the twenty-minute explanation are the knowledge; the coupon and the trash are the replacing; the missing apprentice is the loss that can't be undone. The final sentence of the essay points straight at it: Mr. Halvorsen does not think his disappearing trade is progress.
Why the candidates fail.
- (1) is a claim about one paragraph's subject. It is true of the essay, but paragraph 2 doesn't support it, and it misses why the writer cares.
- (2) names the topic and claims nothing.
- (3) goes far beyond the evidence. The essay is about repair and one craftsman, and nothing in it bears on "society" or on technology in general.
A good implied-thesis answer is exactly as large as the evidence. Too narrow leaves paragraphs unexplained; too broad claims more than the essay shows.
The following is an original passage written for this lesson, in the form of an exam passage. It imagines an essay published in 1926 in a magazine for schoolteachers by a teacher in a one-room school in a farming district.
There are few things a country school can afford, and I have come to believe that the best of them costs almost nothing. I hold that a daily record of the weather, kept by the pupils themselves, is worth more to a school like mine than any science textbook the district could buy, for it teaches children to observe, it teaches them to reckon, and it ties the school to the farms around it.
Observation comes first, because the record demands it. Each morning two pupils read the thermometer on the north wall, measure the rain gauge, and note the direction of the wind and the look of the sky. In our second October, a boy of ten wrote beside his entry that the wind had turned from the south to the east overnight, and asked me whether that meant anything. It did; by afternoon it was raining hard. He had noticed what most grown men in the district would have walked past.
The record teaches reckoning as well. At the end of each month the older pupils total the rainfall, find the average of the morning temperatures, and compare the month with the same month a year before. Sums about real rain in a real gauge hold their attention in a way that sums about imaginary apples never have. Indeed, I have no doubt that every child who keeps such a record will grow up to be a wiser farmer than his father.
Last, and best, the record has made the school a place the farmers visit. They stop on their way to the mill to read the week's figures, which hang by the door, and last June one of them put off cutting his hay for two days because our gauge, and not his own guess, told him the ground was still wet.
Question 1. The clause "for it teaches children to observe, it teaches them to reckon, and it ties the school to the farms around it" functions mainly to
- (A) concede that a weather record has limits as a teaching tool
- (B) preview, in order, the three reasons the rest of the passage develops
- (C) summarize evidence the writer has already presented
- (D) introduce a comparison between the school and the farms
Question 2. The account of the ten-year-old boy in the second paragraph primarily serves to
- (A) illustrate, with a single concrete case, the claim that keeping the record trains children to observe
- (B) set a mood of danger that heightens the reader's sense of the hardships of country life
- (C) suggest that the boy understood the weather better than his teacher did
- (D) provide statistical evidence that the record improves pupils' knowledge of science
Question 3. Which of the following claims is least supported by evidence in the passage?
- (A) The pupils take daily readings of temperature, rainfall, and wind.
- (B) The weather record has made the school a place the farmers visit.
- (C) Every child who keeps such a record will grow up to be a wiser farmer than his father.
- (D) Keeping the record requires pupils to pay close attention to their surroundings.
Show solution
1. (B). The thesis names three benefits, and the next three paragraphs take them in exactly that order, each announced in its first sentence: "Observation comes first," "The record teaches reckoning as well," "Last, and best." (C) is the trap for a student who reads "for it teaches" as a summary, but the clause comes in the first paragraph, before any evidence. (A) is wrong because the clause states benefits, not limits, and (D) mistakes a list of reasons for a comparison.
2. (A). The paragraph's claim is that the record trains observation, and the boy is the concrete instance: he noticed a change in the wind that adults would have ignored. (B) overreads a rainstorm as danger; nothing in the passage is about hardship. (C) contradicts the passage, since the boy asks the teacher what the wind means. (D) misnames the evidence: an anecdote about one boy is not a statistic.
3. (C). The writer offers no evidence at all for a prediction about every pupil's adult life, and the claim is far larger than anything a teacher could observe in a few years: it is a sweeping claim tucked into a well-supported paragraph. (A) is a description of what the pupils do, which the writer is in a position to know. (B) is supported by the farmers reading the figures on their way to the mill and by the one who delayed his haying. (D) is supported by the boy's account.
The method. Read the thesis first and treat it as a map; then, for every claim a question asks about, find the evidence attached to it and compare their sizes.
Where students lose points
On the exam
Multiple-choice reading questions test this skill in several forms: what a piece of evidence, a reference, or an example "serves to" do; which statement best expresses the passage's main claim; what the opening paragraph indicates about how the passage will develop; and which claim is least supported or which evidence would most strengthen an argument. In the rhetorical analysis essay, you need the writer's thesis before you can analyze how the writer defends it, and much of your commentary will explain why the writer chose particular evidence for that audience. Topic 2.4 turns to building your own paragraphs and thesis from claims and evidence.
Check yourself
Question 1
In an essay urging a city to restore its streetcar line, a writer notes that the line's original 1912 cars were built in the city's own foundry, "by the grandfathers of half the people reading this." This detail primarily serves to
- A
clarify how a streetcar line works
- B
amplify the cost of restoring the line
- C
associate the streetcar with the city's pride in its own history and families
- D
exemplify the many transit systems that cities have abandoned
Show answer
C
The detail links the streetcar to something readers already feel warmly about, their city's industry and their own grandparents, so those feelings carry over to the proposal. D is tempting because the detail is a historical example, but nothing presents the line as typical of other cities' systems.
- A
Question 2
A writer claims that "students in our state are sleeping less than they did a generation ago" and supports it with a description of her own exhausted daughter. Is the evidence sufficient for the claim? Explain.
Show answer
No. One student's experience can illustrate the claim but can't show a statewide change over a generation; the claim needs evidence about many students at two points in time, such as survey results from then and now.
Sufficiency depends on the claim's scope. A general trend across a state and across years requires evidence of the same scope, and the anecdote is both a single case and a single point in time.
Question 3
A short essay has three paragraphs. The first describes a town pool that has had a lifeguard shortage for three summers; the second explains that lifeguard pay in the town has not risen since 2009 while nearby towns raised theirs; the third reports that two pools in nearby towns that raised pay filled every position. The essay never states its thesis. Which of the following best states it?
- A
The town's pool has had trouble hiring lifeguards.
- B
Lifeguarding is an important summer job for teenagers.
- C
The town can end its lifeguard shortage by raising lifeguard pay to match nearby towns.
- D
Every town in the region should pay lifeguards more.
Show answer
C
Only C is supported by all three paragraphs: the problem, the cause, and the evidence that the remedy works. A is the claim of the first paragraph alone, B is not argued at all, and D reaches beyond the evidence, which concerns this town only.
- A
Question 4
A passage's thesis reads: "Although a four-day school week would save the district money, it would cost students more than it saves, in lost instruction, in longer days that exhaust younger children, and in a fifth day that many families cannot cover with child care." What does this sentence suggest about how the passage will be organized?
Show answer
It will probably acknowledge the money savings first, then take up the three costs in the order listed: lost instruction, longer days for young children, and child care on the fifth day.
A thesis that opens with "although" signals a concession the writer will address before the main argument, and a list of reasons usually previews the order of the body paragraphs.