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How to read research papers
These last couple of weeks I've been taking my groups of final year project students through the process of starting their literature reviews. There is a separate post on literature reviews on this site here and a post on why you should read academic literature in Computer Science here. This post isn't to do with those topics, this post is about how to read research papers. We often find that if students haven't done much of this sort of reading before their get to their final year getting started can be a bit of a shock. So, this post is designed to help you get started with academic literature and, just as importantly, to help you get the most out of the papers you read in the short space of time you have available (and it is a short space of time, believe me).
Remember the structure of a paper is just like the structure of your thesis
Other posts on this site have discussed the overall structure of your thesis, but in outline this is the sort of structure you should be expecting to produce:
- Introduction should introduce the reader to your research question and the broad context of the research.
- Literature review should describe the work that other people have carried out to answer your (or similar) research questions.
- Method should describe what you did to answer your research question (or to support your thesis, if you think of it that way), and how you went about it.
- Results should evaluate what you have done, and say what answer (to your research question) you have arrived at.
- Conclusions should summarise what you have done and how you answered the research question.
Academic writing (in the sciences) of all sorts follows something like this structure, including all of the papers that you will be reading for your project. There are a couple of exceptions to this rule. One is theoretical papers which sometimes put their "related work" (or literature review) somewhere towards the end of the paper rather than after the introduction. The second exception is survey papers. Surveys are extended literature reviews and, as such, are a good place to start in your own literature reviews. ACM Computing Surveys is a journal that publishes survey papers or you can sometimes find them in reputable journals.
Briefly review each paper for relevance
You don't have time to read everything, so it's important to make sure that what you do read is really relevant to your thesis. So, to check whether a paper is likely to be relevant to you first read the Abstract. This should give you a brief summary of the whole paper. So, at the very least the abstract should give you a good idea of what research question the authors were trying to answer. Next, read the Conclusions. This is also likely to be a summary and may well give you a better idea of what results the authors obtained and what work they did not finish but left for "future work". If that doesn't give you a good enough idea of the relevance of the paper to your own work, try reading the last part of the Introduction. This is usually where the authors summarise what is written in each of the following sections of the paper, so that should give you a much more detailed view of what the rest of the paper contains.
If, after all of that, you think the paper is irrelevant to you, then discard it and move on to something else. Otherwise, you are ready to move on with your reading...
Focus your reading on specific questions
If you just go ahead and read a paper from start to finish the chances are that you won't get very much out of your efforts. You are likely to ramble around the paper, not taking very detailed notes and at the end of your efforts you may not have learned much. A much better way to go about your reading is to keep in mind a number of clear, focussed questions and read the paper with the intention of writing down answers to these questions in your notes. That way you will finish with a clear set of notes that you can be confident will be useful to you when you start writing up.
I would recommend you use this set of questions to guide your reading:
- What research question were the authors asking?
- Why did the authors believe that their research question was important?
- How did the authors go about answering their research question?
- What results did the authors obtain or, what did the authors learn from answering their research question?
You can find a template for some notes here.
Making use of your notes
When you have finished reading you should have a stack of notes on all the papers you have read. This should be a much more concise way to start writing up than having a much bigger stack of papers and (most likely) not much memory of what was in them! So, the next thing to do is decide on the structure of your literature review chapter.
The first paragraph of your chapter should introduce the rest of the chapter. This is a good place to remind the reader of your research question and explain how the current chapter relates to it.
The last paragraph of your chapter should summarise what you have reviewed. This is a good chance to help the reader naviagte around your thesis. Briefly review what you have said in the chapter and refer the reader to the next chapter, explaining how the next chapter follows on from the current one.
The middle part of the chapter is more difficult and, since your writing will depend on your particular research question and the literature you have read, there isn't much generic advice to be given here. However, you can start by reading through your notes and looking for common themes. Think about how best to present the ideas to a reader who has not read the same literature. Do you want to take the reader chronologically through the literature, from the earliest point to the present day? Would it be easier to understand if you split the reading into particular topics that are related? When you have what you think is a good structure, write some section headings into your thesis and think about which papers go in which sections (of course, some papers may well go into several sections). Write the citations into each section using something like EndNote, Mendeley or BibTeX to format them for you. Play around with the structure until you are convinced that it will make sense then write in the details of each section. Make sure you check out this post to help you with your writing.
Why read from primary sources? Or: why reading blog posts is harder, not easier than reading papers
I've been meaning to write this post for a long, long time. Now that I have an enormous pile of marking to get through in double-quick time, I have the perfect excuse for a bit of structured procrastination.
What is a primary source?
A primary source, is an original piece of writing, describing some research and written by the person or team who performed that research. A secondary source, is a description or discussion of a piece of research by someone who has read about the research, but did not carry it out themselves. So, if an academic performs an experiment and writes it up as a journal paper, that paper is a primary source. If another researcher then quotes the paper and cites it in one of their papers, then that is a secondary source. Newspaper articles, magazine articles, wikipedia, and most websites and blog pages are secondary sources. When it comes to scientific research, only writing published in peer-reviewed conferences, journals, books and magazines constitutes a primary source.
What is peer-review and why does it matter?
Even if a paper is a primary source describing some research, that doesn't guarantee that the research is rigorous, reliable and high-quality. To ensure that all academic writing meets basic standards of quality assurance, scientists use peer-review. This means that a number of professional scientists (usually two or more) will read through the work carefully, and critique it before it is published. If the work is of very poor quality, or very badly written, it will be rejected and the authors will have to re-write their papers and try to publish them elsewhere. If the work is of a high enough standard to publish, the authors will be given a list of improvements they must make before the paper goes to print. This way, we ensure that inaccurate, incorrect, or incomprehensible work doesn't get published in high quality conferences and journals.
Why read primary sources?
Students often complain about making the leap from reading textbook-style prose to formal, academic research literature. Part of the problem is that the style of writing is different, and takes some getting used to. More deeply, though, students today have likely grown up with the web and with reading informal, secondary sources, making the change is hard work, and nerve-wrecking for some. Why waste hours wading through pages and pages of long-winded, complicated, weirdly-written prose, when you can read a quick, accessible summary on Wikipedia? Well, of course Wikipedia is a good place to start to get a basic overview of an area and help your understanding of the primary sources you are reading. However, it is absolutely essential to read the primary sources themselves. Why?
Reason 1: secondary sources editorialise
A secondary source will describe some parts of the primary source, but not others. The secondary source will take a particular point of view (i.e. the author will voice their own opinion) and will pick the parts of the primary source that are useful for that discussion. This doesn't necessarily mean that the secondary source is particularly biased (although it might be), it's more that secondary sources are selective in what they discuss. For example, if a paper on Web2.0 discusses the implementation, performance and usability of Web2.0 sites, a secondary source on the subject of usability is likely to leave out any mention of implementation and performance. So, by reading secondary sources you miss out on a lot of the detail of the original work and much of that detail may be very important to you and your work.
It is probably worth saying that there is an important exception to this: survey papers. A good survey paper should be like an extended literature review that discusses, in some detail, the literature available in a broad area of Comptuer Science. These survey papers are a good place to start when writing your own literature review. You can usually find survey papers in well established journals, or specialist survey journals such as ACM Computing Surveys.
Reason 2: secondary sources are sometimes wrong
Every academic field has a number of ideas which are passed on from one generation to the next with little reference back to the original research that generated those ideas. Be somewhat skeptical about this, most of the time there are good reasons to feel assured that this knowledge is sound, especially in fields where mathematical proof is the main way of advancing the field. However, in more subjective or experimental fields (such as Software Engineering or Usability) results can sometimes be misunderstood or misinterpreted over the years.
An example of this is Winston Royce's "Waterfall Method" which (as you probably already know) is a method for organising and planning large programming projects. The central idea in Royce (1970) is very simple and easy to understand: you split the work into a number of different "phases" (requirements gathering, analysis, design, coding, testing, maintenance) and your team performs each phase in turn. There's even a nice image to go with the idea, just to make it nice and easy to understand:
Image source: Wikipedia
For many people, this is where their understanding of the waterfall model stops. But in Royce's original paper there is a long discussion of the drawbacks of organising a project in this manner In fact Royce says that it is "risky and invites failure" (pp. 329). Moving on, the majority of Royce's paper is a list of changes to the sequential model which make it more workable. Some of these are of particular interest, for example "plan testing" is a step that Royce advocates should go with program design. In modern, more "agile" development methods we would advocate writing unit tests around this time, so Royce is presenting a very modern approach. The last modification Royce makes is to "involve the customer" at several points in the process. Again, a much more modern approach that many authors would say goes with agile or "eXtreme" development methods.
The picture Royce paints is not a simple sequential model at all, it's much more complicated than that. Tarmo Toikkanen has written an interesting blog post on this subject. He speculates that the reason people advocate for the basic waterfall method is that the diagram and analogy make it very easy to understand, so people don't delve any deeper into the details. In fact, Toikkanen points out that NATO even have a military standard (DOD-STD-2167) based on Royce's work. [Aside: If you wanted to test Toikkanen's idea that it's the diagram in Royce's paper that leads to the misunderstanding, what experiment would you devise to test that idea?]
More parochially, we often see University students writing something like "in my project I will use the Waterfall Method" sometimes even with a citation. DON'T DO THIS! Read Royce (1970) in full, understand what he's really arguing for, then use a more modern method, or at least use Royce's iterative method found at the end of the paper.
Reason 3: different primary sources may disagree
Research is all about creating and discovering new ideas. Very often primary sources disagree on how best to do that, or they have competing ideas and only through years of research and discussion does a consensus evolve. There are examples of this throughout the history of science. Whether it's the flat Earth debate, Big Bang vs. the Steady State theory, structured programming vs. object oriented programming, through debate, reason, mathematical arguments, prototype systems, models, simulation and all sorts of other techniques, the history of science is full of arguments and competing ideas.
When you read a secondary source, very often whatever "debate" has taken place is already in the past and the author of the secondary source will simply describe the consensus that has since been reached. For example, there were many good reasons for cosmologists to believe in the steady state theory before evidence for the Big Bang became overwhelming. Only by going back to this litereature can we see how the debate unfolded and why the evidence that supported the Big Bang (to do with background microwave radiation in the cosmos which was discovered in the 1960s) was so convincing.
In Computer Science there are also many of these debates. For example, most programming languages do not have a "goto" statement. In fact, Java has a keyword called "goto", but it is not used. In the late 1960s and 70s there was a heated debate about whether "goto" was a safe and useful construct and you can read through that debate in Dijkstra (1968), Knuth (1974) and plenty of other sources. Without going back to these papers, which were written well before the debate was settled, you cannot fully understand the arguments that, eventually, banished the "goto" statement from most modern languages.
Conclusions: reading blog posts is harder than reading papers
So, why did I say in the title of this post that reading blog posts is "harder" than reading papers? Actually reading blog posts may be easier, but in terms of getting a good grade in your project you are unlikely to produce a high quality literature review based on blog posts. Blogs will tend to be selective and biased in their nature. This isn't a criticism of blogs, far from it, blogs are a great place for lively debates. They aren't such a great place to descibe careful, peer-reviewed research in great detail -- that's best left for conferences and journals.
References
How to write a literature review for your final year thesis project
A long time ago I wrote an article on how to pass your final year thesis project, which several students found helpful. In the same vein, this post deals with a particular aspect of the final year project: the literature review.
- How many papers should I read?
- How long should the literature review be?
- Should I read books, articles, or ...?
- Is it OK to reference websites such as Wikipedia?
- Who will read my literature review and what can I assume about their knowledge of the area?
- When should I start the literature review and when should it be finished?
These questions crop up frequently and will be familiar to any readers who are starting their own project. However, when you fully understand the purpose of the literature and how to go about writing one, you begin to realise that these questions are actually not that important. This post is designed to help students make that transition, from not yet understanding what the literature review is for, to having a thorough understanding of its purpose and a clear idea of how to write it up.
- Introduction: should introduce the reader to the broad context of the research and explain why this is an interesting area to work in. So, if your thesis is something to do with mobile computing, you might say something here about why mobile phones are important, why mobile computing is an interesting and important area, and broadly what other researchers are working on. At the end of the chapter you will want to introduce your specific research question, having said why the area you are working in (and therefore your question) is important.
- Literature review: Now you have introduced the reader (who will likely not be an expert in your exact area) to the broad research agenda in the field, and your research question, you can start writing more specifically about your own project. In this chapter you will survey the work that other researchers have done to answer your research question, or related questions. At the end of the chapter you should briefly explain how your own work builds on and differs from the work that has gone before it.
- Method: this chapter should describe what you did to answer your research question (or to support your thesis, if you think of it that way), and how you went about it. You should describe your work in sufficient detail that another researcher could recreate your work to check your results.
- Evaluation: here, you should evaluate what you have done, and say what answer (to your research question) you have arrived at. It may be that in your method you describe some experiments, and this section records your results and analysis of those results. This is an important section -- most students gain or lose marks in either their literature review or evaluation. Key to producing a convincing evaluation is to plan very early in the project what information you will need to write this section. More on that in another blog post.
- Conclusions: should summarise what you have done and how you answered the research question. It may be that your work produced a very clear answer to the question, or it may be that your work points to a need for further research to clarify or confirm your answer. You should refer back to the literature review and summarise how your research differs from (hopefully improves on) the work described in the literature. Make sure you also say what research you would do if you were to continue working on your project.
- References: a list of publications cited in the main text, in Harvard style or similar format.
It is likely that most chapters will be roughly the same size, although the introductory chapter and conclusions are usually slightly shorter than the others. Try to let the lengths of each chapter be guided by the amount of useful and important information you have to convey to the reader, don't impose artificial word limits on yourself.
The area of pervasive, or ubiquitous, computing was founded by Wieser (1991) [ referenced] who predicted that computers would one day be integrated into everyday objects and interact with people seamlessly. Although few such products are available today Weiser’s work has led to the creation of a number of research areas, including ambient intelligence (Eli and Epstein 1998), smart dust (Khan et al, 1999) and the Internet of Things (Brickley et al, 2001). [Sets the historical context of the area and defines related areas.]
An early application of pervasive computing was the active badge location system, described by Want et al (1992), in which users and objects were tagged with an "active" badge which could locate and identify them. This system was based on ultrasound locationing, whereas later systems might use RFID technology to achieve the same effect. [describes how the field has changed over time] Uses of the active badge system included routing phone calls, email alerts and so on to the physical location of the receiver. [contextualises the fundamental research]
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