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Reading & WritingChapter 5: Text Structure and Purpose

Notes

Claim, Evidence, and Explanation Notes

Identify whether existing material states, supports, qualifies, or interprets a claim.

Practice this topic
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Here, all relevant evidence already appears in the passage. The task is to identify its rhetorical role—not to choose new evidence from answer options.

What the SAT is testing

Every topic in this chapter maps to Craft and Structure → Text Structure and Purpose. The official task is rhetorical analysis of one short text: main purpose, a referenced portion's function, or overall structure.

Main idea vs main purpose

Keep these layers separate

Claim

Assertion to evaluate. Example: placement matters.

Evidence

Observation bearing on it. Example: corner panels reduced echoes more.

Explanation

Reasoning link. Example: equal quantity isolates placement.

Content vs function

Distinguish a result from its interpretation. The result may support a claim; the following sentence may explain how or why it does so.

Part-to-whole function
The contribution a referenced phrase, clause, sentence, or detail makes to the passage's development as a whole.

Common rhetorical functions

Useful rhetorical verbs

  • introduces or contextualizes
  • illustrates or exemplifies
  • supports or substantiates
  • clarifies or elaborates
  • contrasts or compares
  • qualifies or limits
  • challenges or questions
  • explains
  • identifies a problem
  • presents a response
  • describes a result
  • establishes significance

Step-by-step strategy

Part-to-whole method

  1. Step 1

    Read the whole passage.

  2. Step 2

    State its overall point or purpose briefly.

  3. Step 3

    Read the exact referenced portion.

  4. Step 4

    Ask what new role it performs.

  5. Step 5

    Connect it to what comes before and after.

  6. Step 6

    Describe the role in your own words.

  7. Step 7

    Choose the option matching that primary role.

Worked examples

Worked example

Referenced-portion function

Researchers proposed that sensor depth affected a tide-pool record. Referenced portion: Sensors at several depths captured changes missed near the surface. This result supports broader placement while leaving other environmental factors open.

Question: Which choice best describes the function of the referenced portion in the text as a whole?

  1. The sentence supplies evidence supporting the earlier claim about sensor placement.
  2. It merely repeats the target's content without advancing the text.
  3. It introduces an unrelated subject.
  4. It performs the role of the opening sentence.
  1. Whole

    State what the full passage develops.

  2. Target

    Sensors at several depths captured changes missed near the surface.

  3. Function

    The sentence supplies evidence supporting the earlier claim about sensor placement.

The sentence supplies evidence supporting the earlier claim about sensor placement.

Why each choice works or fails

  1. Correct: it states content plus relationship.
  2. Content paraphrase, not function.
  3. No topic shift occurs.
  4. Right kind of role, wrong target.
Worked example

Main purpose

Researchers proposed that sensor depth affected a tide-pool record. Sensors at several depths captured changes missed near the surface. This result supports broader placement while leaving other environmental factors open.

Question: Which choice best states the main purpose of the text?

  1. To explain how a specific detail develops and qualifies the passage's central account
  2. To list every fact related to the topic
  3. To persuade readers to adopt an unstated personal motive
  4. To define one isolated word
  1. Topic

    Name the subject without stopping there.

  2. Action

    The text explains and qualifies.

  3. Coverage

    The first choice covers the whole sequence.

To explain how a specific detail develops and qualifies the passage's central account

Why each choice works or fails

  1. Covers action, content, and qualification.
  2. Too broad and inaccurate.
  3. Unsupported purpose.
  4. Wrong task and too narrow.
Worked example

Overall structure

Researchers proposed that sensor depth affected a tide-pool record. Sensors at several depths captured changes missed near the surface. This result supports broader placement while leaving other environmental factors open.

Question: Which choice best describes the overall structure?

  1. It introduces a situation, presents a detail, and explains or qualifies that detail's significance.
  2. It states a conclusion before introducing an unrelated topic.
  3. It lists details without interpretation.
  4. It compares two separate authors.
  1. Move 1

    Introduce the situation.

  2. Move 2

    Present the focal detail.

  3. Move 3

    Interpret or qualify its significance.

It introduces a situation, presents a detail, and explains or qualifies that detail's significance.

Why each choice works or fails

  1. Correct moves and order.
  2. Reversed and unsupported.
  3. Omits interpretation.
  4. Wrong one-text structure.

Common traps and wrong-answer patterns

Difficulty progression
LevelTypical challengeBest response
FoundationDirect role and clear signalName content, then function
MediumPlausible nearby rolesUse before–target–after
ChallengingLayered structure and qualificationPrefer primary global contribution
Mini check

Mini check

A sentence interprets why a result bears on an earlier claim. Its function is to:

  1. connect evidence to the claim
  2. introduce an unrelated topic
  3. select new evidence
  4. correct grammar
Show answer and explanation

Answer: connect evidence to the claim

Interpretation makes the reasoning link explicit.

Key takeaways

Key takeaways

What to remember

  • Claim, evidence, and explanation differ.
  • All material is already in the text.
  • Name the reasoning relationship.
  • Avoid reversed support.
Continue learning

Put these notes into practice

Apply the ideas with SAT-style questions, then reinforce key details with flashcards.