How to read and understand paper

by Jennifer Raff

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.) I always read the abstract last, because it contains 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.

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? You need to be able to succinctly 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.

5. Identify the approach.

What are the authors going to do to answer the specific question(s)?

6. Read the methods section.

Draw a diagram for each experiment, showing exactly what the authors did. Include as much detail as you need to fully understand the work.

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 often find that results are summarized in the figures and tables. Pay careful attention to them! You may also need to go to supplementary online information files to find some of the results. Also pay attention to:

The words “significant” and “non-significant.” These have precise statistical meanings. Read more about this here. 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 people, or 10,000 people? For some research purposes a sample size of 10 is sufficient, but for most studies larger is better.

8. Determine whether 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 OK 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. 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. Find out what other researchers say about the 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? Don’t neglect to do this! 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.

1. 别先读摘要，从导言部分入手。

摘要是论文文首那简短精炼的第一段话。事实上，很多非科研人员在试图建立一种科学观点时，常常就只读一篇论文的摘要部分。（这是一种很糟糕的做法。别这样。）我总是最后才阅读摘要，因为那里包含了对整篇论文的简要概括，我担心无意之间被作者对结果的解读灌输了先入之见。

2. 找出大问题。

“大问题”不是指“这篇论文讲的是什么”，而是“这个领域正在设法解决什么问题”。这有助于你理解为什么要进行这项研究。记得仔细寻找证据分辨哪些文章是有导向性的。

3. 以不超过5句话的篇幅总结背景。

为了解决这一“大问题”，这一领域做过什么努力？之前的工作有什么局限？在作者看来，下一步需要做什么？你得先能够简洁地解释为什么要进行这项研究，才能够理解它。

4. 找出具体问题。

作者在他们的研究中究竟想回答什么问题？这些问题可能有多个，也可能只有一个。把它们写下来。如果是那种验证一个或者多个零假设的研究，把零假设辨别出来。

5. 弄清解决手段。

为了回答这些具体的问题，作者要怎么做？

6. 阅读方法部分。

为每一个实验画出一个图表，画出作者到底做了什么。里面要包含使你全面理解研究工作所需的所有细节。

当然，也有可能摊上这样故弄玄虚的论文。图片来源：http://nature.com

7. 阅读结果部分。

写下一段或几段话，总结每个实验、每幅图解和每张表格的结果。先不要解读结果的意义，写下结果是什么就好。你往往会发现，结果被总结在图解和表格之中了，用心注意它们。你可能还需要查阅在线的补充信息才能发现部分结果。另外，还要注意：

“显著”和“不显著”在统计学上具有精确的含义。 图表中有没有误差线？对一些类型的研究来说，没有标明置信区间可是个大漏洞。 样本大小。研究对象有10个人，还是10000个人？对一些研究目标而言，10个样本足矣，但是对大多数研究来说，样本多多益善。

8. 确定实验结果是否回答了特定问题。

你认为这些结果说明了什么？在想清楚这个问题之前不要继续。就算你被作者的解读改变了想法也不要紧——事实上，如果你还是这种分析型阅读的新手，出现这种情况往往在所难免——但是在阅读其他人的解读之前，先形成自己的解读，确实是一个非常好的习惯。

9. 阅读结论（或解释、讨论）部分。

作者认为结果意味着什么？你同意作者的看法吗？你能不能想出其他的方式解读结果？作者有没有意识到他们的研究存在任何弱点？你有没有发现任何作者遗漏的问题？（别以为他们都万无一失！）他们建议下一步如何做？你同意吗？

10. 回到开头阅读摘要。

摘要与作者在文中的论述相符吗？又是否与你对论文的解读一致？

11. 了解其他研究者对这篇论文的看法。

谁是这一领域（公认或自封）的专家？他们对这项研究有没有什么你没想到的批评？或者大体上都持支持态度？不要省略了这一步！我推荐你在这时候使用谷歌，不过一定要最后再这么做——那样你才能有更加充足的准备，批判性地思考其他人的意见。（编辑：Calo）