Evidence and Support

This is Unit Seventeen of College Composition. Unit Sixteen made the connections between ideas visible. This unit looks at what an argument's ideas rest on: evidence. Carry one idea through this lecture. Evidence does not speak for itself: it must be relevant, sufficient and representative, and the writer's analysis must connect it to the claim. A worked example near the end strengthens a paragraph that used one anecdote as proof. By the end you will be able to name the types of evidence. To test evidence for relevance, sufficiency and representativeness. To connect evidence to a claim and answer counterevidence. And to choose and add evidence for an audience.

Five entries on why claims need support and on the main kinds of evidence.

Claims need support.

CMP 0401 Claims Need Support

A claim says something is true or that some action should be taken, and every claim in an argument needs reasoning and evidence. "The college should extend library hours" is a claim; survey results and usage data are the evidence that makes readers accept it. An unsupported claim asks readers to take the writer's word, which skeptical readers will not do.

The kinds of evidence.

CMP 0402 Types of Evidence

Common types of evidence include facts, statistics, examples, anecdotes, expert opinion, quotations, interviews, definitions and description. Choose the type that best supports each point: a statistic to show scale, an anecdote to show human impact, expert opinion to show professional judgment. Instructors may require certain types of evidence; check the assignment.

Facts in numbers.

CMP 0403 Facts and Statistics

A fact is information that can be proven accurate; statistics are facts expressed in numbers. Statistics show the size of a problem: how many people are affected, how fast something is changing, how two groups compare. A statistic needs context; a number without a comparison or a source rarely persuades.

Stories and instances.

CMP 0404 Examples and Anecdotes

An example illustrates an idea; an anecdote is a short narrative about a specific person or event. An anecdote about one student working long hours to stay in school makes a problem concrete in a way statistics alone cannot. One anecdote shows that something can happen, not how often it happens.

Professional judgment.

CMP 0405 Expert Testimony

Expert opinion is evidence from a professional in the field or someone whose views on the subject are respected. A historian's judgment about a president, or a physician's about a treatment, carries authority because of the speaker's expertise. Expertise is specific; a famous person speaking outside their field is not an expert witness on that subject.

Three entries on testing evidence: is it relevant, sufficient and representative?

Evidence on the point.

CMP 0406 Relevant Evidence

Relevant evidence bears directly on the claim it is meant to support. Evidence about national tuition trends is relevant to a claim about rising tuition, but less so to a claim about one college's financial aid policy. Evidence can be true, credible and interesting and still not support the point at hand.

Enough support.

CMP 0407 Sufficient Evidence

Sufficient evidence means enough support, and strong enough support, to convince the intended audience. A claim about a widespread problem needs more than one case; choose a topic for which you can find strong examples, not weak ones. A skeptical audience needs more evidence than a sympathetic one.

Cases that reflect the group.

CMP 0408 Representative Evidence

Evidence is representative when the cases it draws on reflect the larger group the claim is about. A paper arguing that a welfare system is widely abused cannot rest on one cousin's behavior; statistics show the pattern, and the personal example can then illustrate it. Drawing a broad conclusion from limited experience is a logical error, covered with fallacies in unit thirty.

Six entries on analysis, connecting evidence to a claim, weak support, counterevidence, concession and rebuttal, and objectivity.

Evidence explained.

CMP 0409 Evidence Needs Analysis

Evidence does not speak for itself; the writer's analysis explains what it shows and why it matters. After citing a survey, a writer explains what the numbers mean for the argument, in the writer's own words. A paragraph of stacked quotations with no analysis hands the reader the writer's job.

The link to the claim.

CMP 0410 Connecting Evidence to the Claim

Connecting evidence to a claim means showing readers the link. State the claim, introduce the evidence and name its source, and present it accurately in no more detail than the point needs. Explain in your own words what it shows, then how that finding supports the claim. Where needed, address a limitation, such as a small sample. Readers do not always draw the conclusion the writer intends: a statistic about rising rents can support a claim about housing costs or one about landlord profits, and the writer's explanation decides which.

Support that undermines.

CMP 0411 Weak Support

Support is weak when it is irrelevant, insufficient, unrepresentative or from a source readers will not trust. A single online comment offered as proof of public opinion is weak on several counts at once. Weak evidence can hurt an argument more than no evidence, because it signals that nothing stronger was found.

Evidence against the claim.

CMP 0412 Counterevidence

Counterevidence is evidence that seems to cut against the writer's claim, and strong arguments acknowledge it. A writer arguing for a policy notes a study that found mixed results, then explains why the stronger evidence still supports the policy. Hiding counterevidence works only until a reader who knows it arrives; then the writer's credibility suffers.

Conceding, then answering.

CMP 0413 Concession and Rebuttal

Answering a counterclaim takes two moves: concede what is fair, then rebut. State the counterclaim as its supporters would. Concede what is reasonable, with words such as granted. Rebut with evidence or reasoning, and show how your claim still holds, perhaps in a narrower form. Granted, extending library hours costs money; however, the cost is small compared with the study space students lack. Stating a weakened version of the counterclaim and defeating that is not rebuttal; it is the straw man fallacy, covered in unit thirty. Answer the strongest version.

Evidence without bias.

CMP 0414 Objectivity in Reports

In reports and informational writing, evidence is presented objectively, without the writer's bias shaping what is included. An informational text presents accurate facts, draws inferences that rely on those facts, and uses opinions only when they come from expertise, not emotion. Objectivity also means reporting evidence that complicates the picture, not only evidence that fits.

Four entries on choosing the best detail, adding evidence in revision, a worked example, and evidence for different audiences. The opening idea is paid off at the worked example.

Testing the options.

CMP 0415 Which Detail Best Supports

Choosing the best supporting detail means testing each option. State the paragraph's point, and discard details about the topic but not the point. Prefer specific evidence, a number, a named source or a concrete case, and evidence the audience will trust. Check that the detail fits its place in the argument. To show a bike lane reduced injuries, a hospital's count of cycling injuries before and after beats a resident's remark that the street feels safer. The vivid detail is not always best; choose by what the point needs.

Answering a skeptic's questions.

CMP 0416 Adding Evidence in Revision

Adding evidence in revision means finding the claims a reader would question. Read as a skeptic and mark every claim that makes you ask how the writer knows. Decide what kind of evidence would answer it, find it or note that you need more, place it right after the claim, and add a sentence of analysis. Check that the paragraph still holds one point. Do not add evidence to claims that need none: common knowledge and your own observations of the text under analysis need no outside support.

One anecdote as proof.

CMP 0417 Strengthening a Weak Paragraph

A worked example, constructed for this course, pays off the opening idea. A paragraph argues for more school nurses with a vague claim, one neighbor's story, the phrase "everyone knows this happens all the time," and a dismissal of cost. The claim is sharpened. The anecdote stays, as an illustration, but representative evidence is added: how many schools lack a full-time nurse and how often students are sent home. The cost objection is conceded fairly and answered with evidence, and analysis ties it together. The anecdote was not the problem; using it as proof was.

Evidence by audience.

CMP 0418 Evidence for Different Audiences

The evidence that persuades depends on the audience: what they already know, what they value and whom they trust. A budget committee may respond to costs and savings; parents may respond to stories about children; specialists may require peer-reviewed research. Strong evidence for one audience can be weak for another; choose with your reader in mind.

Look at what you can now do. You can explain why every claim needs support, and name the kinds of evidence, from statistics to anecdotes to expert testimony. You can test evidence for relevance, sufficiency and representativeness, and recognize support so weak it hurts the argument. You can connect evidence to a claim with analysis, acknowledge counterevidence, and answer the strongest objection with concession and rebuttal. And you can choose the detail that best supports a point, add evidence where a skeptic would ask for it, and fit evidence to the audience. Unit Eighteen turns to the reader directly: audience, tone and point of view.