Consistency is extremely important in academic English. Awareness and checking for consistency is key since consistency may not be as important in continental styles and thus writers may forget to look for it. Inconsistency in academic and professional writing in English looks very unprofessional. Clarity for the reader is a guiding principle and consistency helps ensure this.
Being consistent involves choices as often there is more than one possibility. It is generally easier to keep track of your choices while writing than trying to find the inconsistencies after. A good way to do this is to note your choices on a piece of paper as you write. Using a good British dictionary such as the Oxford or Cambridge online dictionaries will also keep the writing consistent.
The following elements should be consistent throughout a text:
Capitalization and format of headings
Example: if the first heading is in bold and capitalized all the way through, then the other headings should be as well. If a piece of writing is for publication, check the publication to see the format used for titles and headings.
British spelling should be used in Europe. This can be checked in a good British dictionary (see above).
British usage should be used. In cases where you have to make a choice, you should be consistent.
Example: data can be used with a singular or plural verb; decide which you prefer and use it throughout your writing.
Example: use of EU Member States or EU member states
Example: use of percent or per cent
The letters used, capitalization, use of articles etc. should be absolutely consistent and identical throughout the text. Otherwise the reader may think you are writing about a different organization or concept. For papers with many acronyms, a list of acronyms and what they stand for is often given in the beginning of the paper.
Format of numbers and dates
In English, the most common formats are for example: 100,000 and 12.2, not 100.000 and 12,2.
Example: consistent use of % or percent in a section discussing findings; it looks odd to sometimes use the percentage sign and sometimes write the word percent
Example: decision maker; decision-making
Tables and figures
Headings for tables and figures including those from other sources should be in the same format, font and size.
All of the above guidelines apply when you create your own tables and figures. Numbers and information should be in the same format throughout each table. The categories in tables and figures should be consistent. Tables and figures with similar information should be in the same font and size. They should look visually like a consistent group.
Example: if you use the word percentage instead of the % sign in a table, you should use it throughout the table
Example: if you use the category male interviewees in one table, you should not use Male Interviewees or men interviewed in another one
Source: the author’s experience proofreading academic journal articles, books, student writing research and project applications