Week 23 — Exposition Models III: Claim Then Support

Week of 2027-02-22 · Download .docx

Objectives

Identify the claim-then-support structure in academic prose and locate the topic sentence, evidence, and closing sentence
Write a deductive paragraph with a specific topic sentence, labeled evidence and reasoning, and a closing sentence that reinforces — rather than restates — the opening claim
Distinguish assertion from demonstration and evaluate whether a paragraph's body sentences demonstrate the topic sentence's claim

Key terms

Deductive structure: An expository pattern that states the general claim first, then provides specific evidence and explanation in support.
Topic sentence: The opening claim of a paragraph — specific, defensible, and requiring the support that follows.
Front-loading: Placing the most important information first so that a reader who skims still grasps the paragraph's central point.
Assertion: A claim stated without support; the starting point that the rest of the paragraph must demonstrate.
Demonstration: The body of the paragraph's work: showing through evidence and reasoning that the topic sentence's claim holds.
Closing sentence: The final sentence of a paragraph that reinforces the topic sentence with earned insight, not mere restatement.
Posit: To put forward a proposition as a starting point for argument; to establish a claim as a premise before supporting it.
Cogency: The quality of being both logically sound and persuasive to a reasonable audience — correct and compelling simultaneously.

The concept

Claim Then Support: The Logic of Academic Paragraph Structure

The claim-then-support structure is the default form of academic expository writing because it is the most navigable, efficient, and verifiable pattern available. The reader knows, from the first sentence of each paragraph, exactly what that paragraph will establish. The body sentences then earn the opening claim through evidence and reasoning. A reader can skim the topic sentence of every paragraph and follow the essay's argument without reading every word — and then return to the body for the proof.

The Topic Sentence as Mini-Thesis

A topic sentence is not an announcement ('This paragraph will discuss...') and not a fact ('Poverty affects many students'). It is a specific, defensible claim that requires the evidence and reasoning to follow. The measure of a strong topic sentence: if you read it in isolation, you should be able to say 'I wonder if that's true — what's the evidence?' A topic sentence that could apply to any paragraph in any essay on any subject is too vague to be useful.

Assertion and Demonstration

Every paragraph enacts a two-part movement: the topic sentence asserts, and the body sentences demonstrate. Assertion puts the claim forward as a premise; demonstration shows through specific evidence and explanation that the claim is accurate. The failure mode of weak expository paragraphs is the assertion-only paragraph — a topic sentence followed by restatements of the same claim at increasing levels of abstraction, without ever providing the specific examples and reasoning that establish it.

The Closing Sentence

The closing sentence is not a restatement of the topic sentence. It is a reinforcement with earned insight — a sentence that reflects back on the topic sentence having seen the evidence. 'The three cases reviewed here establish that the pattern is not coincidental' reinforces without merely repeating. A closing sentence that simply restates the topic sentence signals that the body of the paragraph did not actually move the argument forward.

Worked examples

Example 1: Example 1 — Strong topic sentence: 'Community college transfer rates to four-year institutions remain 15 percentage points below those of students who begin at four-year schools, even when academic preparation is controlled for.' This sentence is specific, cites a measurable gap, includes a methodological note ('when academic preparation is controlled for'), and demands an explanation. It is demonstrably true or false and requires evidence.

Example 2: Example 2 — Assertion versus demonstration: A student writes: 'Social media has damaged communication skills. People now use their phones constantly. They no longer look at each other. This is bad for conversation.' This paragraph asserts and restates but never demonstrates — there is no specific evidence, no cited study, no concrete example, and no reasoning connecting any of the claims. A demonstrative paragraph on the same topic would provide specific evidence (a specific study's finding, a specific observed behavior pattern) and explain why that evidence establishes the opening claim.

Common mistakes

Writing a topic sentence that is too general to require specific support — 'Communication is important' and 'History shows many examples of change' cannot be demonstrated because they are too vague to be contestable. A good topic sentence is specific enough to be wrong.
Restating the topic sentence in the closing sentence rather than reinforcing it — 'Therefore, communication is important in today's world' adds nothing to 'Communication is important.' The closing sentence should show what the paragraph's evidence revealed, not repackage the opening.
Confusing evidence with reasoning — presenting specific examples (evidence) is only the first step; explaining why those examples establish the claim (reasoning) is the step most often omitted. A paragraph with four pieces of evidence and no reasoning sentences has all the materials and none of the argument.

Self-check

Try each one before you look. A miss here costs nothing and tells you exactly what to reread.

1. The primary advantage of the claim-then-support structure for academic writing is:

2. A topic sentence in the claim-then-support structure must be:

3. The difference between assertion and demonstration in a paragraph is:

4. A closing sentence that simply restates the topic sentence in different words is problematic because:

5. Cogency in expository writing means the argument is:

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