HESI A2 · Reading Comprehension · 5 min read · Open lesson

Main Idea and Supporting Details

In this lesson you will

Differentiate between the general topic, the overarching central idea, and paragraph-level main ideas.
Distinguish major supporting details and valid evidence from minor details and anecdotal information.
Apply skimming and scanning techniques to evaluate explicitly stated information, implied ideas, summaries, and passage titles.

Understanding the Topic, Central Idea, and Main Idea

To understand a reading passage, readers must separate the subject being discussed from what the author is saying about it. The topic of a passage is the general subject. In contrast, the central idea is the overarching concept or primary message the author intends to convey. Rather than focusing on a single paragraph or section, the central idea encompasses the entire passage. An effective central idea statement answers what primary point the author is making about the topic. For example, if a speaker discusses exercise, exercise is merely the topic; asserting that regular exercise improves mental health serves as the central idea.

An author can express the central idea explicitly or suggest it implicitly. When explicitly stated, the central idea is often found in the introductory or concluding paragraphs. In an expository passage, a thesis statement directly states the author's central idea. The nature of this message depends on the text type. In informative texts, the central idea is the main point the author explains about the topic, such as a concept, event, or process. In persuasive texts, the central idea is typically the author's primary argument or proposed call to action.

While the central idea governs the entire selection, the main idea of an individual paragraph is the core point that the specific paragraph develops. A main idea functions as an umbrella concept, whereas supporting details rely on the main idea for context. A valid main idea must be broad enough to encompass the paragraph's relevant supporting details without being vague. This core point is most often expressed directly in a topic sentence, which most frequently appears as the first or second sentence of a paragraph. However, a topic sentence can also appear at the very end of a paragraph as a concluding summary. When no direct topic sentence exists, an implied main idea requires the reader to infer the core message from the combined supporting details.

Exam tip. On whole-passage main idea questions, test writers often use two common traps. An answer choice is too narrow if it focuses only on a single supporting fact or isolated paragraph. Conversely, an answer choice is too broad if it encompasses ideas beyond the scope of the passage. Additionally, incorrect main idea options on exams often present true facts from the text that are merely minor details.

Analyzing Supporting Details and Evidence

Supporting details provide specific evidence, examples, reasons, or descriptions that substantiate a main idea. Supporting details are classified as major or minor based on their importance to the main idea: major details develop its key points, while minor details provide less essential examples or elaboration. Major supporting details directly explain or substantiate the paragraph's main idea. Minor supporting details add examples, clarification, or elaboration to major supporting points or the main idea itself. Common types of supporting details include statistics, research findings, expert testimony, and concrete examples.

Transitions reveal how an author connects details within a text. Transitions such as 'for example' and 'specifically' can introduce supporting details, while 'in addition' signals an added point. When an author introduces a differing or opposing point, contrast transitions such as 'however' and 'on the other hand' are used. Recognizing these transition words helps readers trace how an author builds an argument or elaborates on major points.

In many texts, the author puts forward an author's claim, which is an arguable assertion that requires justification and evidence. Evidence consists of verifiable facts, data, research studies, or expert opinions used to support a claim. Readers must evaluate the quality of this evidence. Anecdotal evidence relies on personal stories and is generally less objective than empirical data. Furthermore, relevant evidence directly pertains to and logically substantiates the author's specific claim, whereas irrelevant evidence may be factual, but it fails to support the specific argument being made. To be convincing, a text must present sufficient evidence, which provides enough relevant, credible support to reasonably justify a claim.

Comparison of Supporting Detail Levels
Detail Level	Primary Role	Function in a Summary
Major Supporting Details	Directly explain or substantiate the paragraph's main idea.	Included alongside the central idea to reflect the text's core points.
Minor Supporting Details	Add examples, clarification, or elaboration to major supporting points or the main idea.	Excluded to avoid unnecessary repetition, examples, and tangential explanations.

Locating Explicit Details and Inferring Implied Ideas

Comprehension questions frequently target explicitly stated information. Explicitly stated information is information directly expressed in the text, including stated facts, descriptions, and opinions. Locating explicitly stated information does not require reading between the lines or making inferences. Questions asking who, what, where, or when typically test explicitly stated information. When answering these questions, look for direct statements; correct answers to explicit detail questions may paraphrase information directly stated in the passage.

Readers use targeted reading techniques to navigate explicit information efficiently. Skimming involves reading quickly to gain a general overview of a text's structure and main points. In contrast, scanning involves rapidly moving eyes across a text to locate specific keywords, numbers, or phrases. Skimming helps orient the reader to the text before answering questions, while scanning allows readers to quickly locate exact terms when verifying factual details.

When an author does not state a point directly, readers must deduce the implied main idea by examining how the details fit together. An implied main idea requires the reader to infer the core message from the combined supporting details. Identifying repeated keywords and thematic phrases helps readers recognize the central idea. Additionally, transition words such as 'therefore,' 'thus,' and 'consequently' can introduce conclusions or results that may help reveal the main idea.

Exam tip. When answering explicit detail questions, rely only on what is directly written on the page. Because locating explicitly stated information does not require reading between the lines or making inferences, avoid answer choices that introduce personal deductions. Remember that correct options often paraphrase the original text rather than matching it word for word.

Evaluating Summaries and Selecting Passage Titles

A summary is a concise restatement of the central idea and major supporting points of a passage. An effective summary must be objective and omit the reader's personal opinions or external knowledge. An accurate summary preserves the author's intended meaning and does not distort the author's stance. Furthermore, an accurate summary excludes minor details, repetitive examples, and tangential explanations. A summary should generally reflect the logical organization of the original text.

Recognizing what invalidates a summary is an essential test skill. An answer choice that introduces accurate outside information not found in the passage is an invalid summary. Even if a statement is factually true in real life, it cannot be included if it does not originate in the text. Likewise, summaries that rely on minor supporting details, personal viewpoints, or altered author positions are incorrect.

Selecting an appropriate title follows the same logic as identifying the central idea. An appropriate title reflects the central idea and overall scope of the entire passage. The best title captures both the main topic and the author's primary angle or perspective on that topic. An effective title is neither overly broad nor excessively narrow. A passage title should not focus exclusively on an isolated detail or a single paragraph. Misleading title options often highlight an intriguing secondary detail rather than the central idea.

Exam tip. Watch out for titles and summaries that seem appealing because they mention an interesting fact from the passage. Misleading title options often highlight an intriguing secondary detail rather than the central idea. Always confirm that your title or summary selection captures the overarching central idea and the entire passage rather than an isolated paragraph.

Common mistakes

Choosing an answer that is a true fact from the passage, but functions only as a minor supporting detail rather than the central idea.
Selecting a summary answer choice that includes accurate outside information or personal opinions not found in the original text.
Picking an overly broad title that encompasses ideas beyond the scope of the passage, or an overly narrow title that focuses exclusively on an isolated detail.
Making inferences or reading between the lines on explicit detail questions asking who, what, where, or when.

Summary

The topic is the general subject, whereas the central idea is the overarching concept or primary message the author asserts about that subject across the entire passage.
A paragraph's main idea is an umbrella concept developing a core point, most frequently stated in a topic sentence at the start or concluding summary at the end, or implied by combined details.
Major supporting details directly substantiate the main idea, whereas minor supporting details add elaboration, clarification, or examples.
Claims require evidence; empirical data is more objective than anecdotal evidence, and sound arguments require relevant and sufficient support.
Explicitly stated information requires no inferences, can be located via scanning, and correct answers often paraphrase direct text statements.
An accurate summary concisely restates the central idea and major supporting points, remains objective, excludes minor details, and omits outside knowledge.
An effective passage title reflects the central idea and scope of the text, capturing both the main topic and the author's specific perspective without being too broad or too narrow.

Practice this section

Explained HESI Reading Comprehension questions, no account needed. HESI Reading Comprehension practice test

Check yourself and flashcards

5 practice questions and 18 flashcards for this lesson are in your tests.global account.

Every HESI lesson, one plan

This is an open sample lesson. The full HESI A2 study guide (58 lessons so far) is included with HESI plans, together with the practice question bank.

1 month~~$53.99~~ $26.99
3 months~~$158.99~~ $79.49
Lifetime~~$323.99~~ $161.99

One payment, no subscription.

See HESI plans

Already a member? Log in

25 practice questions on this exam

Each HESI practice test has 25 original questions with the answers explained. No account needed.

Open the HESI practice tests

All HESI A2 lessons

Original lesson written for HESI A2 practice · updated October 15, 2026. Exam names are trademarks of their owners; tests.global is not affiliated with them.