How to read a research paper

Do not start by highlighting. Start by deciding what question you brought to the paper, then use the paper’s own structure to see whether it answers that question.

Write your question first

Before the PDF, one line in your words: “Does this method reduce hospital readmission in adults with heart failure?” or “How do they define afterload?” If you cannot write the line, you are browsing, which is fine — but then do not expect a close-reading session.

Your question decides the depth. A citation check (“do they actually report X?”) is a search. A methods exam is a slow read of two pages. A literature-review pass is titles, abstracts, and figures only.

Three passes, on purpose

A reliable pattern, used in many labs, is to refuse a linear read until you have a map:

1. Pass 1 — skeleton. Title, abstract, section headings, figures and captions, last paragraph of the introduction, first paragraph of the discussion. Stop. Restate the claim. If the claim is irrelevant to your question, stop for good.
2. Pass 2 — argument. Read the introduction’s motivation, the results (not yet every test), and the limitations. Mark terms you cannot define. Do not solve them yet.
3. Pass 3 — mechanism. Methods, appendices, and the sentences you marked. This is the only pass where you should spend serious time on a single paragraph.

The common failure is doing pass 3 on page 2 because the introduction name-drops a model. If the figure already shows the result is not what you needed, you have just donated an hour.

Use the headings the authors paid for

IMRAD (introduction, methods, results, and discussion) is a social contract. Even papers that hide it still have a claim, a procedure, a finding, and a hedge. Search the PDF for those words, or for “we found,” “we measured,” “limitation.” Jump. Read locally.

Figures before prose

In empirical papers, the figures are the results wearing clothes. Read the axes, the sample size if it is there, the error bars, the caption’s last sentence. Then read the paragraph that cites the figure. If they disagree, trust neither yet — that disagreement is the paper.

When a sentence will not yield

Paraphrase it out loud. If you cannot, you do not understand it yet, which is normal. Look one paragraph up for the definition. If the definition is missing, the sentence is using in-group language. That is a good moment to select it and ask for a plain restatement — in PDF Lens, that is Lens beside the page — and then force yourself to close the panel and say the sentence again without looking.

AI will cheerfully explain a sentence in a way that fits a textbook and not this paper. If you cannot point at the clause that justifies the explanation, you borrowed a story.

Stop conditions

• You can state the question, the method in a clause, the main result, and one limitation.
• You know whether you need the paper at all.
• You have page numbers for any claim you plan to reuse.

Related: methodology, limitations, long papers.

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