2.1 Main Idea & Supporting Details
Key Takeaways
The main idea is the central point or message of a passage — it answers "What is this passage mostly about?"
The main idea is often found in the first or last sentence of a paragraph (topic sentence or concluding sentence)
Supporting details provide evidence, examples, facts, or reasons that back up the main idea
Major supporting details directly support the main idea; minor details support major details
A summary captures the main idea and key supporting details without including minor details or opinions
The topic is the general subject; the main idea is the specific point the author makes about the topic
Implied main ideas are not directly stated — you must infer them from the supporting details
On the HESI A2, you will read passages of 400-550 words and answer questions about them
The Reading Comprehension section of the HESI A2 presents passages of approximately 400-550 words on health, science, and general topics. You will answer multiple-choice questions about each passage. The most commonly tested skill is identifying the main idea and its supporting details.
Topic vs. Main Idea
Understanding the difference between topic and main idea is critical:
| Concept | Definition | Example |
|---|---|---|
| Topic | The general subject of the passage (usually 1-3 words) | Hand hygiene |
| Main Idea | The specific point the author makes about the topic (a complete sentence) | Hand hygiene is the most effective way to prevent the spread of infection in healthcare settings |
The topic is what the passage is about. The main idea is what the author is saying about the topic.
Finding the Main Idea
The main idea can be found in several locations:
- First sentence of the passage — most common location (deductive organization)
- Last sentence of the passage — used as a conclusion (inductive organization)
- Implied — not directly stated; must be inferred from the details
Strategy for finding the main idea:
- Ask yourself: "What is the ONE point the author is making?"
- Look for the sentence that all other sentences support or explain
- Eliminate details that are too specific — the main idea is broad enough to cover the entire passage
- Eliminate statements that are too broad — the main idea should be specific to this passage
Supporting Details
Supporting details are the facts, examples, statistics, reasons, and evidence that back up the main idea.
| Type | Description | Example |
|---|---|---|
| Major supporting details | Directly support and develop the main idea | "Studies show that proper hand washing reduces healthcare-associated infections by 40%" |
| Minor supporting details | Support a major detail with additional specifics | "The 2019 WHO study involved 3,200 healthcare workers across 15 countries" |
Identifying Detail Types in Questions
HESI A2 questions may ask:
- "Which detail best supports the main idea?" → Look for major supporting details
- "According to the passage, which of the following is true?" → Find the specific detail in the passage
- "Which statement is NOT a supporting detail?" → Find the option that is irrelevant or contradicts the passage
Summarizing
A good summary:
- States the main idea in your own words
- Includes only major supporting details
- Does NOT include minor details, personal opinions, or new information
- Is significantly shorter than the original passage
HESI A2 Tip: When a question asks for the "best summary," eliminate answers that include minor details, opinions not stated in the passage, or information too broad or too narrow.
Paragraph Organization
Understanding how paragraphs are organized helps you locate information quickly:
Deductive (General to Specific):
- Main idea stated FIRST, followed by supporting details
- Most common organization in academic and healthcare writing
- "Hand hygiene is the most effective way to prevent infection. Studies show that..."
Inductive (Specific to General):
- Details are presented first, building to the main idea at the END
- "Studies in 15 countries showed reduced infection rates... Therefore, hand hygiene is the most effective prevention method."
Topic Sentence vs. Thesis Statement:
- A topic sentence states the main idea of a single paragraph
- A thesis statement states the main idea of an entire passage or essay
- Both serve as the "roadmap" for what follows
Paraphrasing vs. Summarizing vs. Quoting
| Skill | Definition | Use When |
|---|---|---|
| Paraphrasing | Restating an idea in your own words (similar length) | You want to rephrase for clarity |
| Summarizing | Condensing to main idea and key points (shorter) | You need the essential information only |
| Quoting | Using the exact words from the source | The specific wording is important |
On the HESI A2, questions may ask you to identify the best paraphrase or summary of a passage. The best paraphrase maintains the original meaning without copying the exact words.
What is the difference between a topic and a main idea?
They are the same thing — both refer to the subject of the passage
The topic is a general subject (1-3 words); the main idea is the specific point about the topic (a sentence)
The topic is always stated in the first sentence; the main idea is in the last sentence
The main idea is broader than the topic
Where is the main idea most commonly found in a paragraph?
In the middle of the paragraph
In the second-to-last sentence
In the first sentence of the paragraph
Only at the end of the passage
Which of the following is a major supporting detail for the main idea "Regular exercise improves cardiovascular health"?
The local gym offers a 20% discount for new members
Studies show that 30 minutes of daily exercise reduces heart disease risk by 35%
Exercise shoes should be replaced every 300-500 miles
Many people prefer exercising in the morning rather than the evening
Which of the following are characteristics of a good summary? (Select all that apply)
Select all that apply
Includes the main idea
Includes all minor details from the passage
Is shorter than the original passage
Includes the reader's personal opinions
Contains only major supporting details
Is written in the reader's own words
An implied main idea is one that:
Is stated clearly in the first sentence
Is not directly stated but must be inferred from the details
Appears only in the conclusion of the passage
Is stated by the author in a separate summary paragraph
When a HESI A2 question asks "What is this passage mostly about?", it is asking for the:
Author's opinion
Main idea
Most interesting detail
Conclusion of the passage
Sections you finish are checked off in the contents.