How to read a scientific paper

How to read a scientific paper

You’ve just completed your studies and your thesis supervisor has asked you if would like to consider a career in the academy. How exciting! 

If you agree, you’ll embark on a challenging journey to become a knowledgeable and influential researcher. You will have to learn many new skills and likely how to read a scientific article is probably the most important one. Reading papers will take most of your time and it is very important that you learn to do it efficiently.

Reading papers contributes to form an educated opinion on a scientific subject, to become familiar with the current research in a field, and to distinguish between good and bad interpretations of research. It is different from other forms of reading and it usually requires different levels of depth depending on the fact that you are informing yourself on a domain, understanding if a paper is relevant to your research, looking for references for the article that you are writing, or reviewing someone else’s work. 

Don’t worry: you can learn it too. Like any other skill, it just takes patience and practice!

The 3-pass approach

In this article I am going to introduce a 3-pass method to efficiently read papers. Depending on your current task, you might need to go read the article in more or less depth. The first pass, for instance, is enough to understand if a paper is relevant or not to your research. If you’re forming your understanding of a research area, you might want to proceed to the second pass. If you are working on a research project of the field or you are reviewing the paper, you might want to have all the 3 passes. Generally speaking, you should give all the articles all the 3-passes, but due to time constraints you might need to stop earlier.

Before proceeding to the first pass, anyway, you should take a mental note of the authors, their institutional affiliations, and the journal. After some time, you will be able to identify influential authors in the field, the most respected institutions, and the most prestigious journals. Notice that tools like Academic Scout looks up for institutions and checks the impact factor of journals for you. The impact factor measures how influential is a journal.

How papers are structured

Most papers are organised in the same way. They include: 

  • Title: a one sentence summary of the paper
  • Abstract: a slightly longer summary introducing the background, the contribution and the results
  • Introduction, a section that presents the answer to the research questions with respect to the background:
    • The problem being investigated (the background)
    • The motivation for the research or why the problem is hard and the impact of finding a solution
    • A summary of the state of the art in the field
    • Introduces the contributions of the paper (usually a bullet list, often introducing the hypotheses, the research questions and the experiments to address them
  • Methods, provides enough details to understand and replicate the research:
    • Explains how the problem was studied
    • Identifies the procedure followed
    • Explain new methodology in details
    • Includes details on the datasets, frequency of observations, types of recorded data, etc.
  • Results, presents the findings and explains their meaning:
    • shows how the new results are contributing to the body of scientific knowledge
    • follows a logical sequence based on the tables and figures presenting how they answer the research questions
  • Discussion
    • describes the meaning of the results with respect to what was already known about the subject; 
    • indicates how the results relate to expectations and to the literature previously cited
    • explains how the research has moved the body of scientific knowledge forward
    • outlines the next steps for further study 
  • Acknowledgements: recognize various contributions of other workers
  • References: the sources of previously published work

The Acknowledgements section is optional and Title, Abstract and References are expected to be part of every paper. The initial letters of the remaining sections (Introduction, Methods, Results, and Discussion), or IMRaD, are used to identify this format. Notice that these sections might have slightly different names or be organised in a slightly different way but almost all the papers follow this structure. Also notice that a scientific paper should not be read linearly from beginning to end, so it’s important that you identify these sections and proceed to read them according to the suggestions in the 3-pass method.

The 1st pass

Now that you know what to expect to find in a paper, let’s see what the 1st pass of reading consists of.

Some people start with the Abstract, but I suggest you skip it and start from the Introduction. If you’re deciding if the paper is relevant to your research, reading the Abstract is fine as it is a shorter compendium of the article. However, it is usually biased as it also serves as an introduction to the authors’ position and results.

  • Proceed to the Introduction and try identify the big research question, or the ultimate goal of the research field of the article.
  • Summarise the background in 5 sentences or less: you can use this summary to later file the paper in your personal scientific library. It contributes to form your understanding of what has been done in this field and more or less which is the state of the art for this discipline.
  • Then identify the specific research questions that the authors are trying to address. These questions are often implicitly stated through a list of contributions. Use these to understand what kind of research the authors did, and which is their take about the big research question.
  • Finally recognise where the authors introduce their approach to solve their specific research questions. You might want to summarise it as a sentence and add it to the summary that you just created.

Notice that if you can’t clearly identify these parts, the paper might be poorly written.

The 2nd pass

By now, you should just have completed the 1st pass on the paper. You should have a summary of the Introduction that frames the work with respect to its research field, and if it is a paper worthy to read in more details. If so, or if you have to review the paper, you might want to go read it in more details and proceed to a 2nd pass.

In this second step, you should read the Methods section first and then proceed to the Results section. 

  • When you read the Methods section, you might want to sketch a diagram to summarise the approach or methodology that the authors are describing to solve their research problems. At this stage, you shouldn’t worry too much to understand the theory behind in perfect details as you are just getting familiar with the authors’ method. 
  • Before proceeding to the Results section, stop for a second to think critically about the paper. You should know by now, what problems the authors are tackling and what other approaches have been tried (from 1st pass) and what approach is being used. Try to imagine how the results might be. Then read this section, focus on the tables and pictures and see if they match with your expectations. Does the results answer the authors’ research questions? This will help you to form your opinion on the described approach. And it might be a good feedback for the authors if you are reviewing their paper. Eventually summarise the results in a sentence and add it to the summary you created during the 1st step.

Notice that if you can’t clearly understand these parts, the paper might be poorly written.

The 3rd pass

Once you completed the 2nd pass, if you decide that the paper is worthy an extra pass (or if you’re reviewing the paper) spend again some time to critically think about it before proceeding any further.

Try to think what would you have done if you had to conduct the same research. Would you have used the same methodology or would you have done something different? Again, this is great feedback for the authors if you are reviewing this article. 

Moreover, try to mentally re-implement their experiments. Have you had any problems? If so, this is the best time to read again the Methods section and become familiar with every subtle detail and learn the theory behind the approach.

Now that you have a good understanding on the background, the approach and the results from previous passes, think what would be your conclusions and form your own opinion on the solution that is presented in the paper. Finally proceed to reading the Discussion section and compare your opinion with the authors’ view. Do you agree with them? Do you think they have omitted something, or they should include some other details in the experiments to make their point clearer? Are they aware of it? Have they promised to address it in future works? As always, this is great feedback for the authors of a paper that you are reviewing. In any case it is a great way to improve your awareness on a given research field and to get better professionally.

Notice that if you find this part confused, the paper might be poorly written.

Last but not least, read the Abstract. Do you think it is an honest summary for the paper? Or have the authors tried to oversell their research? Search online for tweets and general articles commenting on the paper. What do other researchers think of this work? If available, you might want to add a sentence on the consensus of the scientific community about the paper to your summary and eventually file the paper in your personal scientific library using it for indexing.

Properly reading a scientific paper is a key skill that every researcher has to acquire to be successful. As every skill, you can acquire it with patience and practice. In this post, I have introduced a 3-pass approach to make your reading as efficient as possible. There are tools that makes the reading of scientific articles easier. Academic Scout, in particular,  allows you to add notes to the papers that you discover online and automatically finds for you tweets and articles about them.

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