How to read and understand a scientific paper: a guide for non-scientists

Update (1/3/18) I’ve been overwhelmed with requests for the shorter guide, and the email address below no longer works. So I’ve uploaded a copy of the guide for anyone to download and share here: How to read and understand a scientific article. Please feel free to use it however you wish (although I’d appreciate being credited as the author). I apologize to everyone who emailed me and didn’t get a response! If you would like to let me know who you are and what you’re using it for in the comments below, I’d love to hear!

Update (8/30/14): I’ve written a shorter version of this guide for teachers to hand out to their classes. If you’d like a PDF, shoot me an email: jenniferraff (at) utexas (dot) edu.

Last week’s post (The truth about vaccinations: Your physician knows more than the University of Google) sparked a very lively discussion, with comments from several people trying to persuade me (and the other readers) that their paper disproved everything that I’d been saying. While I encourage you to go read the comments and contribute your own, here I want to focus on the much larger issue that this debate raised: what constitutes scientific authority?

It’s not just a fun academic problem. Getting the science wrong has very real consequences. For example, when a community doesn’t vaccinate children because they’re afraid of “toxins” and think that prayer (or diet, exercise, and “clean living”) is enough to prevent infection, outbreaks happen.

“Be skeptical. But when you get proof, accept proof.” –Michael Specter

What constitutes enough proof? Obviously everyone has a different answer to that question. But to form a truly educated opinion on a scientific subject, you need to become familiar with current research in that field.  And to do that, you have to read the “primary research literature” (often just called “the literature”). You might have tried to read scientific papers before and been frustrated by the dense, stilted writing and the unfamiliar jargon. I remember feeling this way!  Reading and understanding research papers is a skill which every single doctor and scientist has had to learn during graduate school.  You can learn it too, but like any skill it takes patience and practice.

I want to help people become more scientifically literate, so I wrote this guide for how a layperson can approach reading and understanding a scientific research paper. It’s appropriate for someone who has no background whatsoever in science or medicine, and based on the assumption that he or she is doing this for the purpose of getting a basic understanding of a paper and deciding whether or not it’s a reputable study.

The type of scientific paper I’m discussing here is referred to as a primary research article. It’s a peer-reviewed report of new research on a specific question (or questions). Another useful type of publication is a review article. Review articles are also peer-reviewed, and don’t present new information, but summarize multiple primary research articles, to give a sense of the consensus, debates, and unanswered questions within a field.  (I’m not going to say much more about them here, but be cautious about which review articles you read. Remember that they are only a snapshot of the research at the time they are published.  A review article on, say, genome-wide association studies from 2001 is not going to be very informative in 2013. So much research has been done in the intervening years that the field has changed considerably).

Before you begin: some general advice

Reading a scientific paper is a completely different process than reading an article about science in a blog or newspaper. Not only do you read the sections in a different order than they’re presented, but you also have to take notes, read it multiple times, and probably go look up other papers for some of the details. Reading a single paper may take you a very long time at first. Be patient with yourself. The process will go much faster as you gain experience.

Most primary research papers will be divided into the following sections: Abstract, Introduction, Methods, Results, and Conclusions/Interpretations/Discussion. The order will depend on which journal it’s published in. Some journals have additional files (called Supplementary Online Information) which contain important details of the research, but are published online instead of in the article itself (make sure you don’t skip these files).

Before you begin reading, take note of the authors and their institutional affiliations. Some institutions (e.g. University of Texas) are well-respected; others (e.g. the Discovery Institute) may appear to be legitimate research institutions but are actually agenda-driven. Tip: google “Discovery Institute” to see why you don’t want to use it as a scientific authority on evolutionary theory.

Also take note of the journal in which it’s published. Reputable (biomedical) journals will be indexed by Pubmed. [EDIT: Several people have reminded me that non-biomedical journals won’t be on Pubmed, and they’re absolutely correct! (thanks for catching that, I apologize for being sloppy here). Check out Web of Science for a more complete index of science journals. And please feel free to share other resources in the comments!]   Beware of questionable journals.

 As you read, write down every single word that you don’t understand. You’re going to have to look them all up (yes, every one. I know it’s a total pain. But you won’t understand the paper if you don’t understand the vocabulary. Scientific words have extremely precise meanings).

Step-by-step instructions for reading a primary research article

1. Begin by reading the introduction, not the abstract.

The abstract is that dense first paragraph at the very beginning of a paper. In fact, that’s often the only part of a paper that many non-scientists read when they’re trying to build a scientific argument. (This is a terrible practice—don’t do it.).  When I’m choosing papers to read, I decide what’s relevant to my interests based on a combination of the title and abstract. But when I’ve got a collection of papers assembled for deep reading, I always read the abstract last. I do this because abstracts contain a succinct summary of the entire paper, and I’m concerned about inadvertently becoming biased by the authors’ interpretation of the results.

2. Identify the BIG QUESTION.

Not “What is this paper about”, but “What problem is this entire field trying to solve?”

This helps you focus on why this research is being done.  Look closely for evidence of agenda-motivated research.

3. Summarize the background in five sentences or less.

Here are some questions to guide you:

What work has been done before in this field to answer the BIG QUESTION? What are the limitations of that work? What, according to the authors, needs to be done next?

The five sentences part is a little arbitrary, but it forces you to be concise and really think about the context of this research. You need to be able to explain why this research has been done in order to understand it.

4. Identify the SPECIFIC QUESTION(S)

What exactly are the authors trying to answer with their research? There may be multiple questions, or just one. Write them down.  If it’s the kind of research that tests one or more null hypotheses, identify it/them.

Not sure what a null hypothesis is? Go read this, then go back to my last post and read one of the papers that I linked to (like this one) and try to identify the null hypotheses in it. Keep in mind that not every paper will test a null hypothesis.

5. Identify the approach

What are the authors going to do to answer the SPECIFIC QUESTION(S)?

 6. Now read the methods section. Draw a diagram for each experiment, showing exactly what the authors did.

I mean literally draw it. Include as much detail as you need to fully understand the work.  As an example, here is what I drew to sort out the methods for a paper I read today (Battaglia et al. 2013: “The first peopling of South America: New evidence from Y-chromosome haplogroup Q”). This is much less detail than you’d probably need, because it’s a paper in my specialty and I use these methods all the time.  But if you were reading this, and didn’t happen to know what “process data with reduced-median method using Network” means, you’d need to look that up.

Battaglia et al. methods

You don’t need to understand the methods in enough detail to replicate the experiment—that’s something reviewers have to do—but you’re not ready to move on to the results until you can explain the basics of the methods to someone else.

7. Read the results section. Write one or more paragraphs to summarize the results for each experiment, each figure, and each table. Don’t yet try to decide what the results mean, just write down what they are.

You’ll find that, particularly in good papers, the majority of the results are summarized in the figures and tables. Pay careful attention to them!  You may also need to go to the Supplementary Online Information file to find some of the results.

 It is at this point where difficulties can arise if statistical tests are employed in the paper and you don’t have enough of a background to understand them. I can’t teach you stats in this post, but here, here, and here are some basic resources to help you.  I STRONGLY advise you to become familiar with them.


-Any time the words “significant” or “non-significant” are used. These have precise statistical meanings. Read more about this here.

-If there are graphs, do they have error bars on them? For certain types of studies, a lack of confidence intervals is a major red flag.

-The sample size. Has the study been conducted on 10, or 10,000 people? (For some research purposes, a sample size of 10 is sufficient, but for most studies larger is better).

8. Do the results answer the SPECIFIC QUESTION(S)? What do you think they mean?

Don’t move on until you have thought about this. It’s okay to change your mind in light of the authors’ interpretation—in fact you probably will if you’re still a beginner at this kind of analysis—but it’s a really good habit to start forming your own interpretations before you read those of others.

9. Read the conclusion/discussion/Interpretation section.

What do the authors think the results mean? Do you agree with them? Can you come up with any alternative way of interpreting them? Do the authors identify any weaknesses in their own study? Do you see any that the authors missed? (Don’t assume they’re infallible!) What do they propose to do as a next step? Do you agree with that?

10. Now, go back to the beginning and read the abstract.

Does it match what the authors said in the paper? Does it fit with your interpretation of the paper?

11. FINAL STEP: (Don’t neglect doing this) What do other researchers say about this paper?

Who are the (acknowledged or self-proclaimed) experts in this particular field? Do they have criticisms of the study that you haven’t thought of, or do they generally support it?

Here’s a place where I do recommend you use google! But do it last, so you are better prepared to think critically about what other people say.

(12. This step may be optional for you, depending on why you’re reading a particular paper. But for me, it’s critical! I go through the “Literature cited” section to see what other papers the authors cited. This allows me to better identify the important papers in a particular field, see if the authors cited my own papers (KIDDING!….mostly), and find sources of useful ideas or techniques.)

Now brace for more conflict– next week we’re going to use this method to go through a paper on a controversial subject! Which one would you like to do? Shall we critique one of the papers I posted last week?

UPDATE: If you would like to see an example, you can find one here


I gratefully acknowledge Professors José Bonner and Bill Saxton for teaching me how to critically read and analyze scientific papers using this method. I’m honored to have the chance to pass along what they taught me.

Do you have anything to add to this guide? A completely different approach that you think is better?  Additional questions?  Links to other resources? Please share in the comments!

496 thoughts on “How to read and understand a scientific paper: a guide for non-scientists

  1. mrtnlm June 30, 2015 / 3:58 am

    Reblogged this on mrtnlm and commented:

    Very informative piece about how to read and understand a scientific paper.

    There are a lot of discussions going on right now about whether GMO’s are safe or about how vaccines are killing us. There is a lot of pseudoscience involved in these discussions and although that’s a bad thing, it’s quite logical. People tend to be fearful and easily manipulated, so these discussions are ideal for the fear mongerers who aren’t going to get you with extraordinary science.

    By screaming fire and murder, you will get a lot of people behind your statements..

    Enjoy this reading!

    • John Siviour April 21, 2016 / 1:11 am

      Thank you for the significant detail…and associated effort…associated with your article. A great resource, whether a vaxxer, anti-vax or a “seeker”. Kudos.

  2. Lambert August 12, 2015 / 2:12 pm

    Very important one,I am following this approach for my grad school starting this Fall.

  3. Mats Eriksson November 2, 2015 / 8:29 am

    Interesting article! However, the link to the null hypothesis paper is not valid anymore. “Not sure what a null hypothesis is? Go read this, then go back…”

    Keep the good work up regarding vaccinations!

    • Jennifer Raff November 2, 2015 / 8:32 am

      Thanks for the heads up! I’ll replace the link.

  4. Steven R Cox November 30, 2015 / 7:24 pm

    Dr. Raff,

    Intelligent design is the wave of the future. Blindly rejecting an hypothesis, which happens to be the most direct and obvious hypothesis, is a way to understanding nothing. The neo-Darwinian model of random mutation and natural selection is going the way of the phlogiston theory of combustion (suggest googling phlogiston theory). Let’s all strive for the truth regardless of where it takes us, because the truth benefits all.

  5. Kay Germano January 28, 2016 / 10:04 pm

    Love this, and I will be sharing this with my Research Methods undergraduate class when we start dissecting journal articles! Thank you so much!

  6. Nathan Pruzina February 9, 2016 / 11:58 am

    I believe you should read the abstract first so you can decide whether to read the entire paper.

  7. manisha February 11, 2016 / 8:30 am

    A very useful write up…helped to gain clarity over the paper reading process specifically critical reading…

  8. Michael March 30, 2016 / 8:35 am

    Thank you for the interesting article. A question : Does it really matter if the producer of the paper has an agenda or not ? If they are biaised in their interpretation, or even the methods, wouldn’t this be visible in the way the experiements were carried out ?

    Does the background of the producer become determinant for the value of the research itself ? If it is, what % of scientific research out there that is clean from agendas ?

    Thank you.

    • Jennifer Raff March 31, 2016 / 2:28 pm

      I guess the answer is “it depends.” We all have some degree of bias (or at least perspective), the question is whether that interferes with doing good science. My point is being aware of where a person is coming from can be helpful in this regard.

      • Michael March 31, 2016 / 5:39 pm

        Thank you so much.

  9. Michael April 1, 2016 / 4:58 pm

    Hi again, I just would like to ask, have you posted any article about how to create a protocol for experiments and which ways the quality of the protocol is ensured ? If yes, I’d love to read it.

  10. WiVdeP April 19, 2016 / 8:54 am

    Loved the article, great for critical reading… I’m a lawyer and I find this very useful.

  11. Francois Blot April 19, 2016 / 10:19 am

    I think you can had in the “FINAL STEP” to look at the Citation Analysis. How often this article has been cited by other researches. But you cannot rely only on this bibliometric measurement, you also need to know how the article is cited (for or against).

  12. Grenovica April 19, 2016 / 10:46 am

    Dear Dr. Raff,
    Am I allowed to translate this into Bulgarian and reblog/repost it? I am an educated and certified translator and interpreter from German, but I think the vocabulary is manageable and I am very careful about doing research on topics or languages I am familiar but not professional competent with.
    Thank you!
    Eva Stefanova

    • Jennifer Raff April 19, 2016 / 11:21 am

      Please feel free! Would you email me a copy? jennifer (dot) raff (at) ku (dot) edu Thanks!

      • Grenovica April 19, 2016 / 2:52 pm

        Of course! Might not happen next week, but when I’m ready, I’ll send you the text. Thank you very very much!

  13. briavarner April 19, 2016 / 8:44 pm

    Reblogged this on bria varner and commented:

    I was reading something else and ran across this very nice guide on how to go about reading scientific papers. Seeing as how I tend to throw around peer-reviewed articles here rather frequently, I thought this might be helpful. I enjoyed it!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s