Main Idea and Theme
Main-idea and theme questions ask you to state, in one sentence, what a whole passage is about (main idea) or what general truth about life or human behavior it implies (theme). This is the highest-yield domain in ISEE Reading Comprehension: at the Middle and Upper Levels the section gives 36 questions in 35 minutes, and at the Lower Level 25 questions in 25 minutes, so you cannot afford to re-read a passage hunting for a topic sentence. Train yourself to name the point after the first read.
Main idea versus theme
A main idea is a claim about the text: it covers every paragraph and could not be deleted without gutting the passage. A theme belongs to narrative, poetry, and personal-essay passages; it is implied rather than stated and must be expressed as a full sentence about people in general, not as a one-word topic. "Perseverance" is a topic; "Persistence matters more than raw talent" is a theme.
Apply the scope test
Ask of each choice: does this cover the whole passage (correct), only one paragraph (too narrow), or more than the passage actually claims (too broad)? Wrong answers are usually true statements that are too small.
Worked example
A passage describes a marine biologist who tags sea turtles for three seasons with no recoveries, keeps going, and in the fourth season recovers tags that confirm a migration route. Choices: (A) how to tag sea turtles; (B) a scientist's patience produced an important discovery; (C) sea turtles migrate long distances; (D) why research funding is scarce. (B) is correct because it accounts for the whole narrative. (A) and (C) are accurate but describe only parts; (D) is a passing detail.
Traps that cost marks
- Choosing a topic label ("Sea turtle migration") instead of a claim.
- Choosing an answer that is true but too narrow.
- Accepting extreme wording: proves, always, never, all scientists.
- Stating a theme as a single abstract noun rather than a sentence.