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A Help Or A Hindrance?

The dos and don'ts of using abbreviations

· Writing tips

Abbreviations are shortened forms of a word or phrase. They pop up a lot in scientific writing – not surprising, since science is filled with long, complicated words that are just crying out to be shortened. But abbreviations don’t always help your reader. In this blog post, I explain how abbreviations can improve the flow of your writing – and why it is sometimes best to avoid them.

No introduction needed

Many scientific words are better known by their abbreviations, such as DNA (‘deoxyribonucleic acid’) and PCR (‘polymerase chain reaction’). In most cases, using these abbreviations improves the flow and clarity of your writing. Consider the following:


Blood samples were sent to a laboratory for deoxyribonucleic acid analysis. Certain locations on the deoxyribonucleic acid chain were examined by polymerase chain reaction.


When we use the abbreviations, the text is much easier to read and the meaning is still clear:


Blood samples were sent to a laboratory for DNA analysis. Certain locations on the DNA chain were examined by PCR.


Because these abbreviations are so well-known, a definition is usually not necessary. The same is true for abbreviated Latin terms, such as ‘i.e.’ for id est (that is), ‘e.g.’ for exempli gratia (for example), and ‘et al.’ for et alii (and others).

Clarify the unfamiliar

However, non-standard abbreviations can make reading more difficult for those who are not familiar with your topic. Try reading the following:


The SN is part of the MB and plays an important role in reward-seeking and addiction.


Unless you have written it (or can read minds), this sentence is impossible to understand.


To make your meaning clear, it is important to spell out all non-standard abbreviations when they are first used. This is usually done by spelling out the term in full and then giving the abbreviated form in parentheses directly after:


The substantia nigra (SN) is part of the midbrain (MB) and plays an important role in reward-seeking and addiction.

Still in doubt?

If you are not sure whether an abbreviation should be defined, check whether it is recognised in the medical subject headings (MeSH) browser of the National Library of Medicine. All standard abbreviations are accepted in this browser. Also check the guidelines of your chosen journal for any specific instructions. Some journals provide a list of accepted abbreviations. These may include subject-specific abbreviations that are well established in the journal’s field. For example, The Journal of Cell Biology accepts FCS (‘foetal calf serum’) and PDGF (‘platelet-derived growth factor’) as standard abbreviations because they are common cell-culture reagents.


If in doubt, always define an abbreviation when you first use it. This will keep your meaning clear and avoid potential mix-ups with similar abbreviations. For example, SARS is a common abbreviation for ‘severe acute respiratory syndrome’, but may be confused with SARs (‘structure activity relationships’) or SAR (‘systemic acquired resistance’).


Use abbreviations sparingly

Less is more when it comes to abbreviations. Why? Think of your poor reader. Abbreviations disrupt the reading process – each time your reader comes across an abbreviation, they have to remember (or even worse, look up) what the abbreviation means. Compare the following sentences:


AC was the most common indication for LT, followed by HCC and VH.


Well, that makes no sense. Let’s try again:


Alcoholic cirrhosis was the most common indication for liver transplantation, followed by hepatocellular carcinoma and viral hepatitis.


That’s better. The latter sentence is much easier to understand. Yes, it is filled with long, subject-specific words, but reading long phrases is quicker than looking up multiple abbreviations.


So help your reader by using abbreviations sparingly. There is no set rule, but journal guidelines and style guides generally say a word should be used 3–5 times before it can be abbreviated.

So what are the no-no's?

Do not use abbreviations to reduce your word count. Some journals impose a strict word count on research articles, but there are better ways to use fewer words than filling your manuscript with annoying abbreviations. Try cutting out unnecessary clutter – this will reduce your word count and make your manuscript more readable.

Switching between abbreviations and full names is another no-no. This will confuse your reader. Once you have defined an abbreviation, use it consistently throughout your paper.

Some parts of your manuscript are better off without abbreviations. These are:

  • The title. Writing your title out in full will ensure that potential readers understand what your paper is about. Your title is also used to index your paper in literature databases. If it contains non-standard abbreviations, then potential readers may not find it while searching the literature.
  • The Abstract. This is the home page for your manuscript; it summarizes your aims, methods, findings, and conclusions – and is the only part of your paper that many people will read. So it must be clear and easy to understand without reference to the main text. Avoid abbreviations if possible – and if you must use them, make sure they are defined.
  • Figures, tables, and legends. Your reader should be able to interpret your results from your figures and tables without reference to the main text. So undefined abbreviations are a no-no.

Useful if used properly

Abbreviations will either make your writing easier or more difficult to read. It depends on how you use them. Following the tips outlined in this article can help you get the balance right and keep your reader happy.

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Help your reader understand you

Claire Bacon is a former research scientist with professional qualifications in copyediting and medical editing. She edits scientific research papers and teaches courses on scientific writing.