Over at Tor.com, Jo Walton is surprised that people skim over boring bits of novels. While she explicitly excludes non-fiction from her discussion, this immediately made me think of Timothy Burke’s How to Read in College, which offers tips to prospective humanities and social science majors on how to most effectively skim through huge reading assignments for the information that’s really important.
I’ve mentioned this before, but I don’t think I’ve done a science version. I’ve been doing more reading of journal articles lately than I have in a while, though, and it occurs to me that similar skills come into play in the sciences, so I thought I would provide a quick guide for the most effective way to skim a scientific paper for the information you really need. This is, as most of my posts are, primarily applicable to experimental papers in physics, but I’ll try to make it as general as possible.
The first and most important point is to Know What You’re Looking For. Different bits of information are found in different places and in different forms, so what you’re looking for will determine where you look, and how you find it.
For example, if you’re just trying to get a general sense of what a given paper is about, it’s often enough to read only the introduction and conclusion. If you’re just after a specific numerical result, it’s probably in the abstract, or toward the end of the paper.
You should also be aware that what you’re looking for may not be in the paper you’re reading. If you want a sense of the context of a field, you’re often looking for a reference to earlier work, possibly a review article. If you want the gory details of a measurement technique, you may very well be looking for some reference to an earlier or longer paper by the same group (a sentence of the form “using the method of [citation of earlier paper]”), or, even more annoyingly, some online supplement to the article you have.
Next, you should Know the Structure. While real scientific papers don’t follow the strict “Abstract-Introduction-Procedure-Results-Conclusion” format we force undergraduates to learn, there are some similarities. Most papers have an introductory section that contains nearly all of the references to past work by other people, a middle section where they talk about their results and how they got them, and a concluding section with a discussion of possible implications of the results.
If the paper you’re reading is in a field you know well, you can probably skip the first page or so, and get right to the part where they talk about their actual measurements. If it’s from another field, you may not be able to read much past the first page, at least in detail. If you just want the result and what it means, you want to look near the end.
There are some subfield-specific sections to know about, as well. For example, a paper about a precision measurement will usually include a section devoted to the analysis of systematic errors. This can be a great source of colorful anecdotes (elevators needing to be disabled to ensure good data, and that sort of thing), but unless you’re a hard-core precision measurement junkie, you can probably skip most of it to get to the final numbers.
The fastest way to get an idea of what’s going on is to Look at the Pictures. Most experimental papers will have figures showing the arrangement of their apparatus, and often include things like timing diagrams showing how they did something. You can figure out a lot from these figures, and their captions. this is especially true in journals with tight page limits, as the captions are usually printed in a smaller font, so some experimental details are often crammed in there where they take up less space. In Science and Nature papers, figure captions don’t seem to count against your page limit, so you’ll often see really massive figure captions in those journals, that are like mini articles unto themselves.
The final data are generally presented in graphical form as well, so if you want a quick idea of the quality of a paper and its results, you’re generally looking for something that will be in a figure, so that’s the first place to look. If you find a figure with data that look interesting, but aren’t immediately clear from the picture and caption, scan the nearby text for the figure label (“Our results are plotted in Fig. 2″), and read backwards and forwards from there.
Speaking of that, Learn to Read in Both Directions. If you want to skip around in a paper, you’ll need to know how to read backwards from a figure reference as well as forwards. If the paragraph about the results contains an acronym whose meaning isn’t obvious, scan backwards through the text for the first appearance of it (or at least a point before which is doesn’t appear– some authors aren’t good about putting the acronym right with its definition, but expect you to figure it out when it appears in the next line). If one of the axes of a graph is labeled by an unfamiliar Greek letter, it’s probably a combination of some measured quantities and physical constants, so you need to scan backwards until you find the first appearance of that symbol, which ideally will be in a simple equation defining it.
I’m sure I’m leaving out some critical tips, but these are the ones that strike me as the most critical tips for quickly finding what you need in a scientific article. If you know how to do these things, you can get a good idea of what’s going on in a paper much more quickly than you can by reading the entire thing. Sometimes, this is enough to get you the critical fact you need, and let you move on to something else; other times, it just shows you that a paper is good/important enough that you need to sit down and read the whole thing.