Structure of Journal Articles
For any method of reading, you will find that taking notes while reading the articles is the most time effective approach, and will keep you from having to re-read them. In addition, you will want to make note of the nomenclature used within the article. While each field of study typically has common variable names or symbols that are used consistently between researchers, there may occasionally be some variation, particularly in older papers.
The abstract is a brief summary of the paper. In it, the authors explain what their research is about, why they conducted this experiment, their key results, and the impact they believe their results will have. The reason that authors write an abstract is exactly why you read it first, to be able to tell quickly if the article is relevant to your research. If so and you are skimming the article on a first read, then continue to the Discussion section. Otherwise, the Introduction is next.
For a first reading, you may be wondering, why not read the Introduction first? Typically, the author discusses the reason for conducting the research in detail, and why it is important. More significantly, the authors provide the background information of their research, including a summary of their own literature review. This section can often be the longest section of the paper, and is challenging to read due to the amount of technical information. For these reasons, you want to be sure that the paper is truly relevant to your research before investing your time in reading it. For a first reading, you may want to skim this section. For subsequent readings, however, it will be important for you to understand all of the concepts presented.
As you read through the introduction, you typically need to read other papers in order to make sure that you understand all the background information. If there are any concepts you do not understand, now is the time to learn about them in order to have a full understanding of the research. Note any important concepts or information which may be of interest. You should also obtain copies of the most important referenced articles to obtain a better understanding of the research, especially if you notice several authors referring to the same paper. This often indicates that this is a landmark paper associated with a fundamental contribution that has had significant impact on the field, and is required reading. Finally, you should understand any assumptions made by the authors, which will be laid out in this section.
Methods (and materials)
For experimental research which involves collection and analysis of data, this section is left to the end for the first reading. It is very important, though, as it provides details that will likely be useful when you conduct your own experiments. Information in the methods section may also help explain different results obtained by multiple researchers. Additionally, in order to validate any research, experiments should be repeatable by other researchers. Without a clear methodology section detailing the methods and materials used, it is not easy to replicate results.
As noted earlier, for research focused on development of new methodology, this section should be read in the natural order of the paper (i.e. after the introduction). For these articles, this section is perhaps the most critical. It contains the essence of the work, while the results and discussion sections may provide numerical or empirical results illustrating the new methodology.
This may be the shortest section of the paper, although it can be lengthy if it contains graphs and figures for visual representation of the results. The authors may present the raw data or summary statistics from their research, usually without interpretation. As you read this section, be sure that you are able to interpret and understand what is being presented. When reviewing a figure, be sure you know what the axes represent, what units are used, and what the curve or any other graph represents. It is often a good idea first to look at any graphics, and then read through the results, referring back to the graphs as needed.
In this section, the authors summarize their results, and may explain their conclusions based on the results. (Sometimes there is a separate conclusions and recommendations section). It is important not to assume that their results are valid or that their conclusions are correct. At this point, critical thinking becomes an important tool. You must decide whether you agree with the logic of their conclusions. Are there errors in the assumptions they made (you may need to find these in the introduction or methods sections)? Finally, are their results useful to your research? If you are doing a first read, you should now return to the Introduction section.