Your paper’s abstract is critical because many researchers will read that part only, rather than reading the entire paper. Therefore, it is critical that it provides an accurate and sufficiently detailed summary of your work so that those researchers can understand what you did, why you did it, what your findings are, and why your findings are useful and important. Your abstract must be able to stand alone, that is, to function as an overview of your study that can be understood without reading the entire text. Readers who become interested in learning more details than can be included in the abstract will inevitably proceed to the full text. Therefore, the abstract does not need to be overly detailed; for example, it does not need to include a detailed methods section.
Even though the abstract is one of the first parts of your paper, it should actually be written last. You should write it soon after finishing the other sections, while the rest of the manuscript is fresh in your mind, enabling you to write a concise but comprehensive summary of your study without overlooking anything important. Requirements for abstracts differ among journals, so the target journal’s instructions for authors should be consulted for specific details. Despite differences among journals, there are a few general rules that should be obeyed when writing an abstract:
• The word limit should be observed; 250 words is probably about average and commonly adopted as a word limit for the abstract, but many journals request shorter abstracts (for example, Nature Articles and BBRC both have a 150-word limit) while many others (for example, BioMed Central journals) allow longer ones. This is one good reason why the target journal should be identified before you write your paper. • Technical jargon should be avoided so that the abstract is understandable for a broad readership, although what is considered “technical” may vary depending on the target journal’s audience (check the journal’s website for details of their readership). For example, “a test of anxiety” would generally be clearer than “elevated plus-maze test” in an abstract unless the journal was specifically targeted to behavioral researchers. Usually, there simply isn’t enough space in the abstract to define and explain technical terminology. If such terminology is unavoidable, it should be defined in simple terms where it is first used. • Like technical jargon, abbreviations should be limited as much as possible, although their acceptability may again depend on the target journal. For example, HIV is likely to be acceptable in abbreviated form by most journals. By contrast, RT-PCR might be considered acceptable by a journal reporting molecular biology techniques, but would it need to be spelt in full (reverse transcriptase polymerase chain reaction) in most journals at first use. Many journals provide a list of acceptable abbreviations on their websites. Necessary abbreviations used three or more times should be defined at first use; however, abbreviations used only once or twice should be spelled out in full unless doing so causes the word limit to be exceeded. Abbreviations that are defined in the abstract will need to be defined again at first use in the main text. • Although some journals do allow references to be cited in the abstract, the vast majority do not. Therefore, unless you plan to submit to a journal that allows it, you should not cite references in your abstract.
If we look at the instructions to authors for BBRC, we can see the following guidelines: • The Abstract should be on page 2, i.e., after the title page • The Abstract must be a single paragraph that summarizes the main findings of the paper in fewer than 150 words. • A list of up to 10 keywords useful for indexing or searching should be included after the Abstract.
Some journals request structured abstracts divided into sections such as background, objectives, methods, results, and conclusions. Clinical journals may require additional or alternative sections, such as ‘patients’. Therefore, it is again necessary to check the target journal’s instructions for authors to determine the particular formatting/outline requirements prior to writing.
Abstracts are frequently followed by a list of keywords selected by the authors. The instructions for authors will state how many keywords are required and may even provide a list of recommended keywords. Choosing appropriate keywords is important, because these are used for indexing purposes. Well chosen keywords enable your manuscript to be more easily identified and cited. Thus, the keywords should be as specific to your manuscript as possible, and general terms, which could apply to an enormous number of studies, should be avoided.
Examples: Let’s consider some appropriate keywords for the following title: “Region-specific neuronal degeneration after okadaic acid administration”.
Good keywords would be: okadaic acid, hippocampus, neuronal degeneration, MAP kinase signaling, and possibly mouse (or rat or whatever experimental animal was used).
Poor keywords would be: neuron, brain, OA (as an abbreviation), regional-specific neuronal degeneration, and signaling. These terms are simply too general.