How to read and understand a research paper

Researchers spend a great deal of time reading research papers. However, this skill is rarely taught,

At AMASA EDUCATIONAL SERVICES we always advice our students registered through us for International Universities abroad, to learn to do so which will help you in your University Education in future.

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Later in another article we will discuss about how to write a research paper. In this article we consider how to read a research paper. 

Researchers must read papers for several reasons: to review them for a conference or a class, to keep current in their field, or for a literature survey of a new field. A typical researcher will likely spend hundreds of hours every year reading papers. Learning to efficiently read a paper is a critical but rarely taught skill. Beginning graduate students, therefore, must learn on their own using trial and error. Students waste much effort in the process and are frequently driven to frustration. Thus it is better to start reading now itself so that you wont feel completely alien when you are asked to read one in you lecture room when you start you Studies.

You will need to carefully read a research paper if you are asked to review it, or if it is relevant to your own research. We might also later discuss how to skim a paper, so that you can decide whether a paper is worth a careful reading.

When you read a research paper, your goal is to understand the scientific contributions the authors are making. This is not an easy task.

It may require going over the paper several times. Expect to spend several hours to read a paper.

Here are some initial guidelines for how to read a paper:

Read critically: Reading a research paper must be a critical process. You should not assume that the

authors are always correct. Instead, be suspicious.

Critical reading involves asking appropriate questions. If the authors attempt to solve a problem, are they solving the right problem? Are there simple solutions the authors do not seem to have considered? What are the limitations of the solution (including limitations the authors might not have noticed or clearly admitted)?

Are the assumptions the authors make reasonable? Is the logic of the paper clear and justifiable, given the assumptions, or is there a flaw in the reasoning?

If the authors present data, did they gather the right data to substantiate their argument, and did they appear to gather it in the correct manner? Did they interpret the data in a reasonable manner? Would other data be more compelling?

Read creatively: Reading a paper critically is easy, in that it is always easier to tear something down than to build it up. Reading creatively involves harder, more positive thinking.

What are the good ideas in this paper? Do these ideas have other applications or extensions that the

authors might not have thought of? Can they be generalized further? Are there possible improvements that might make important practical differences? If you were going to start doing research from this paper, what would be the next thing you would do?

Make notes as you read the paper:  Many people cover the margins of their copies of papers with notes. Use whatever style you prefer. If you have questions or criticisms, write them down so you do not forget them. Underline key points the authors make. Mark the data that is most important or that appears questionable. Such efforts help the first time you read a paper and pay big dividends when you have to re-read a paper after several months.

It would be easier if more research papers were well written... but again, we will discuss writing later on.

After the first read-through, try to summarize the paper in one or two sentences:

Almost all good research papers try to provide an answer to a specific question. (Sometimes the question is a natural one that people specifically set out to answer; sometimes a good idea just ends up answering a worthwhile question.) If you can succinctly describe a paper, you have probably recognized the question the authors started with and the answer they provide. Once you have focused on the main idea, you can go back and try to outline the paper to gain insight into more specific details. Indeed, if summarizing the paper in one or two sentences is easy, go back and try to deepen your outline by summarizing the three or four most important subpoints of the main idea.

If possible, compare the paper to other works:

Summarizing the paper is one way to try to determine the scientific contribution of a paper. But to really gauge the scientific merit, you must compare the paper to other works in the area. Are the ideas really novel, or have they appeared before? (Of course nobody expects you to be experts and know the areas ahead of time)

It is worth mentioning that scientific contributions can take on many forms. Some papers offer new ideas; others implement ideas, and show how they work; others bring previous ideas together and unite them under a novel framework.

Knowing other work in the area can help you to determine which sort of contribution a paper is actually making. For this you should keep on reading more & more research papers which will improve your knowledge in the subject.

For many years I have used a simple approach to efficiently read papers. This paper describes the ‘three-pass’ approach and its use in doing a literature survey.

THE THREE-PASS APPROACH

The key idea is that you should read the paper in up to three passes, instead of starting at the beginning and ploughing your way to the end. Each pass accomplishes specific goals and builds upon the previous pass: The first pass gives you a general idea about the paper. The second pass lets you grasp the paper’s content, but not its details. The third pass helps you understand the paper in depth.

The first pass :
The first pass is a quick scan to get a bird’s-eye view of the paper. You can also decide whether you need to do any more passes. This pass should take about five to ten minutes and consists of the following steps:

1. Carefully read the title, abstract, and introduction

2. Read the section and sub-section headings, but ignore everything else

3. Read the conclusions

4. Glance over the references, mentally ticking off the ones you've already read

At the end of the first pass, you should be able to answer the five Cs:

1. Category: What type of paper is this? A measurement paper? An analysis of an existing system? A description of a research prototype?

2. Context: Which other papers is it related to? Which theoretical bases were used to analyse the problem?

3. Correctness: Do the assumptions appear to be valid?

4. Contributions: What are the paper’s main contributions?

5. Clarity: Is the paper well written?

Using this information, you may choose not to read further. This could be because the paper doesn’t interest you, or you don’t know enough about the area to understand the paper, or that the authors make invalid assumptions. The first pass is adequate for papers that aren’t in your research area, but may someday prove relevant. Incidentally, when you write a paper, you can expect most reviewers (and readers) to make only one pass over it. Take care to choose coherent section and sub-section titles and to write concise and comprehensive abstracts. If a reviewer cannot understand the gist after one pass, the paper will likely be rejected; if a reader cannot understand the highlights of the paper after five minutes, the paper will likely never be read.

The second pass :
In the second pass, read the paper with greater care, but ignore details such as proofs. It helps to jot down the key points, or to make comments in the margins, as you read.

1. Look carefully at the figures, diagrams and other illustrations in the paper. Pay special attention to graphs. Are the axes properly labeled? Are results shown with error bars, so that conclusions are statistically significant? Common mistakes like these will separate rushed, shoddy work from the truly excellent.

2. Remember to mark relevant unread references for further reading (this is a good way to learn more about the background of the paper).

The second pass should take up to an hour. After this pass, you should be able to grasp the content of the paper. You should be able to summarize the main thrust of the paper, with supporting evidence, to someone else. This level of detail is appropriate for a paper in which you are interested, but does not lie in your research speciality. Sometimes you won’t understand a paper even at the end of the second pass. This may be because the subject matter is new to you, with unfamiliar terminology and acronyms.

Or the authors may use a proof or experimental technique that you don’t understand, so that the bulk of the paper is incomprehensible. The paper may be poorly written with unsubstantiated assertions and numerous forward references. Or it could just be that it’s late at night and you’re tired. You can now choose to: (a) set the paper aside, hoping you don’t need to understand the material to be successful in your career, (b) return to the paper later, perhaps after reading background material or (c) persevere and go on to the third pass.

The third pass :

To fully understand a paper, particularly if you are reviewer, requires a third pass. The key to the third pass is to attempt to virtually re-implement the paper: that is, making the same assumptions as the authors, re-create the work. By comparing this re-creation with the actual paper, you can easily identify not only a paper’s innovations, but also its hidden failings and assumptions. This pass requires great attention to detail. You should identify and challenge every assumption in every statement.

Moreover, you should think about how you yourself would present a particular idea. This comparison of the actual with the virtual lends a sharp insight into the proof and presentation techniques in the paper and you can very likely add this to your repertoire of tools. During this pass, you should also jot down ideas for future work. This pass can take about four or five hours for beginners, and about an hour for an experienced reader. At the end of this pass, you should be able to reconstruct the entire structure of the paper from memory, as well as be able to identify its strong and weak points. In particular, you should be able to pinpoint implicit assumptions, missing citations to relevant work, and potential issues with experimental or analytical techniques.

DOING A LITERATURE SURVEY

Paper reading skills are put to the test in doing a literature survey. This will require you to read tens of papers, perhaps in an unfamiliar field. What papers should you read? Here is how you can use the three-pass approach to help. First, use an academic search engine such as Google Scholar or CiteSeer and some well-chosen keywords to find three to five recent papers in the area. Do one pass on each paper to get a sense of the work, then read their related work sections. You will find a thumbnail summary of the recent work, and perhaps, if you are lucky, a pointer to a recent survey paper. If you can find such a survey, you are done.

Read the survey, congratulating yourself on your good luck. Otherwise, in the second step, find shared citations and repeated author names in the bibliography. These are the key papers and researchers in that area. Download the key papers and set them aside. Then go to the websites of the key researchers and see where they’ve published recently. That will help you identify the top conferences in that field because the best researchers usually publish in the top conferences.

The third step is to go to the website for these top conferences and look through their recent proceedings. A quick  scan will usually identify recent high-quality related work.

These papers, along with the ones you set aside earlier, constitute the first version of your survey. Make two passes through these papers. If they all cite a key paper that you did not find earlier, obtain and read it, iterating as necessary.

This disciplined approach prevents you from drowning in the details before getting a bird’s-eye-view. It will allow you to estimate the amount of time required to review a set of papers.

REFERENCES

[1] T. Roscoe, “Writing Reviews for Systems Conferences,”                                                    
      http://people.inf.ethz.ch/troscoe/pubs/reviewwriting.pdf.

[2] H. Schulzrinne, “Writing Technical Articles,”
      http://www.cs.columbia.edu/ hgs/etc/writingstyle.html.

[3] G.M. Whitesides, “Whitesides’ Group: Writing a Paper,”  
      http://www.che.iitm.ac.in/misc/dd/writepaper.pdf.

[4] ACM SIGCOMM Computer Communication Review Online,
      http://www.sigcomm.org/ccr/drupal/.

[5] http://ccr.sigcomm.org/online/files/p83-keshavA.pdf

[6] http://www.eecs.harvard.edu/~michaelm/postscripts/ReadPaper.pdf

By : G.A. Amodha Galgamuwa