Deep Dive

LSAT Reading Comprehension Primary Purpose: why too narrow and too broad are both wrong

Primary Purpose questions ask what a passage as a whole is trying to accomplish — and the correct answer sits in a surprisingly narrow zone between two equally common wrong-answer traps: too narrow, and too broad.

The Goldilocks zone

A Primary Purpose answer that's too NARROW captures only one paragraph or one supporting detail, missing the passage's overall arc. An answer that's too BROAD describes something so general it could apply to dozens of unrelated passages on completely different topics. The correct answer sits precisely between these — specific to THIS passage, but covering its full scope.

Too narrow (a common wrong answer)

“To describe one scientist's specific experimental method.” This might accurately describe paragraph 2, but ignores everything the passage does in paragraphs 1, 3, and 4.

Too broad (the other common wrong answer)

“To discuss a scientific debate.” This is true of thousands of passages about thousands of different debates — it says nothing distinguishing about THIS passage specifically.

Correctly scoped

“To explain why a specific scientific theory gained acceptance despite initial resistance from the field.” This captures the passage's actual arc — specific to its content, but covering the whole structure, not just one piece.

Why the too-narrow trap is more common than people expect

It's tempting to answer based on whichever part of the passage you remember most vividly — often the most recent paragraph you read, or the part with the most interesting detail. Primary Purpose questions punish this recency bias specifically, since the correct answer needs to reflect the passage's FULL structure, not just its most memorable section.

A structural test before touching answer choices

Before looking at options, try to state the passage's purpose in one sentence covering its beginning, middle, and end. If your one-sentence summary only naturally describes part of the passage, you likely need to revise it before it's ready to be matched against answer choices.

Passage structure	What a correct Primary Purpose answer must reflect
Presents a theory, then a challenge to it	Both the theory AND the challenge, not just one
Describes a process, then evaluates it	The description AND the evaluation together
Compares two viewpoints	The comparison itself, not just one viewpoint's content

If an answer choice would work equally well as the primary purpose of a different, unrelated passage, it's too broad. If it only accounts for part of this passage's structure, it's too narrow. The correct answer should feel like it could ONLY describe this specific passage — in full.

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