6.3 Understanding Abbreviations

Abbreviations are required to some degree in almost all doctoral theses, but most style guides and guidelines will recommend that authors keep their use of abbreviations to a bare minimum or use only standard abbreviations (such as SI units) for weights and measures. Some guidelines will suggest that abbreviations be used predominantly in parenthetical material, footnotes and endnotes, bibliographies and reference lists, and tables, figures and appendices, but in the fields of science and technology, abbreviations tend to be used quite extensively, and many theses use abbreviations of some kind in the running text as well as in ancillary material. Virtually all scholarly guidelines will ask that any but the most common abbreviations (again, SI units are a good example) and those used more frequently and better known than the corresponding full terms (‘CD,’ ‘AIDS’ etc.) be defined (or written out in full) on first use (in the main text as well as the abstract and other ancillary material) to ensure that readers will understand both the abbreviations and what the author is saying about the abbreviated terms and concepts. They also tend to suggest that abbreviations only be used if practical or necessary, that they be employed only for terms and names that are used several times in a chapter or thesis (‘five times or more’ according to the Chicago Manual of Style, 2003, p.558) and that a list of abbreviations and their definitions be provided if many nonstandard abbreviations are used in a document. If you use nonstandard abbreviations in your thesis, you should therefore check university and department guidelines and follow any specific advice provided. In the absence of such advice, the best policy is to define or explain any nonstandard abbreviations briefly but accurately, which can usually be done quite simply by using the full term followed by the abbreviation in parentheses, as in ‘American Psychological Association (APA) style is used in many theses in the social sciences.’ Each abbreviation should then be used with precision and consistency throughout the thesis.

If a list of abbreviations is required for your thesis, the list should observe alphabetical order according to the abbreviations (rather than the full terms) so that readers can easily find specific abbreviations (see also Sections 4.6.2 and 5.5.2). The following, for example, might be the opening items in a list of abbreviations:

ANOVA: Analysis of variance

CG: Control group

CI: Confidence interval

ES: Effect size

G1: Group 1

G2: Group 2

All abbreviated and full versions of terms in the list should correspond exactly to those used in the chapters and other parts of the thesis. The same forms should be used in your abstract if you include (and are allowed to include) abbreviations there (see Section 4.2), and keep in mind that abbreviations used in your abstract should be defined there as well, even if they are also used and defined in the main text of the thesis. In some cases, abbreviations will need to be defined (or redefined) on first use in each chapter, which can be useful because it renders your meaning clear even if a reader consults only a single chapter of your thesis. Abbreviations used in other parts of your thesis, such as tables, figures and appendices, should also be defined in those parts (once again using the same forms and terms as elsewhere in the thesis) so that the tables, figures and appendices can be understood without the reader referring to other parts of the thesis for definitions (see Sections 4.4.1 and 4.6.1). The abbreviations used in bibliographies and reference lists tend to be standardised and thus usually do not require definition, but any that are not standard (abbreviated names of corporate authors, for instance, such as ‘MLA’ or ‘WHO’) should be defined, and any referencing abbreviations that are also used in other parts of the thesis (‘et al.,’ for instance) should take the exact same form in all places (with or without italic font, for instance, in the case of ‘et al.’). As a general rule, abbreviations other than those used more frequently and better known than their full versions (‘AIDS’ and ‘DVD’ are good examples) should be avoided in titles and headings (see Section 6.1); although abbreviations are sometimes allowed in this context (do check your guidelines), the full terms are clearer and should be preferred unless they are unwieldy. The abbreviations can instead be introduced and defined (or simply used if already defined) in the sentences following a heading.

There are several different kinds of abbreviations and not all of them are true abbreviations, though they are commonly grouped under that one term in guidelines and style guides. A true abbreviation is formed when the end of a word is omitted; the full stop that tends to close this sort of abbreviation represents the missing letters (‘assoc.,’ ‘ref.,’ ‘Wed.,’ ‘Nov.’ etc.), but the full stop does not always appear. Frequently referred to as an abbreviation is a contraction in which the middle of the word is missing; because the final letter of the word is included, a full stop is not necessary and often does not appear (‘attn’ ‘Mr,’ ‘Jr,’ ‘St’ etc.), but there are exceptions. An acronym, strictly speaking, is formed from the initial letters of the words that make up a term or name and can be read as a single word (as ‘NASA’ and ‘UNICEF’ can be). When in common use, acronyms are sometimes written as a normal word bearing only a single initial capital (e.g., ‘Nasa’ and ‘Aids’). Also generally referred to as an acronym but not a true acronym is an initialism, which is also formed from the initial letters of the words that make up the term or name, but initialisms are pronounced as single letters (as ‘BBC’ and ‘IQ’ are), not as words. The use of acronyms in sentences differs slightly from that of initialisms, so the distinction between the two is important. As special typographical characters or letters of the alphabet, symbols or signs (such as ‘%,’ ‘£,’ ‘$,’ ‘§,’ ‘+’ and ‘=’) are more abstract representations than the other kinds of abbreviations and they can take a myriad of forms both generally and in different fields of study, but they, too, represent a word or concept in a shortened form.

6.3.1 Lowercase or Uppercase Letters in Abbreviations

Abbreviations of all kinds can be formed with lowercase or uppercase letters or a combination of the two: ‘NASA,’ ‘UNICEF,’ ‘IQ,’ ‘BBC,’ ‘assoc.,’ ‘a.m.,’ ‘kph,’ ‘attn,’ ‘Mr,’ ‘Dr’ and ‘Ph.D.’ As these examples show, acronyms and initialisms tend to use all capitals, while true abbreviations and contractions tend to use all lowercase letters or an initial capital followed by lowercase letters, but there are exceptions: ‘Unicef’ can be written with only an initial capital, for instance, ‘kph’ is technically an initialism and ‘a.m.’ and ‘p.m.’ often appear in capitals in American English (‘A.M.’ and ‘P.M.’), sometimes without the full stops (‘AM’ and ‘PM,’ though the stops should definitely be used if there is any chance of confusion with ‘AM’ meaning Anno Mundi: see the list of Latin abbreviations in Section 6.3.11). The Chicago Manual of Style (2003, p.559) helpfully points out that ‘noun forms are usually uppercase (HIV, VP), adverbial forms lowercase (rpm, mpg).’ Single letters used as symbols can be uppercase (e.g., ‘R’ meaning ‘multiple correlation’ or ‘U,’ the Mann–Whitney test statistic) or lowercase (‘d’ for Cohen’s measure of sample effect size or ‘z’ for a standardised score).

6.3.2 Full Stops with Abbreviations

True abbreviations, as I noted above, generally take one or more full stops (‘Nov.,’ ‘Thurs.’ and ‘Ph.D.,’ with the last lying somewhere between a true abbreviation and an initialism), whereas contractions do not (‘Mr,’ ‘Mrs’ and ‘St’). This is not necessarily predictable, however, and ‘Ph.D.’ (along with other degree titles) can be written without the stops (‘PhD,’ ‘MA’ and ‘MSc’) as well as with them, while ‘St’ without a stop usually means ‘Saint’ and ‘St.’ with a stop means ‘Street.’ Acronyms and initialisms usually do not use full stops (‘UNICEF’ and ‘REM’), though a single capital letter abbreviating a word is generally followed by a stop (in personal names, for instance – ‘S. Taylor’ and ‘S.J.T. Smith’ – but not in all referencing systems, so do check the guidelines you are following); this is not the case with compass points (‘N,’ ‘S,’ ‘E’ and ‘W’), however, or when an entire name is abbreviated (‘JFK’ for ‘John Fitzgerald Kennedy’) or when the letter is actually a symbol (e.g., ‘R’ or ‘U’ in statistics). Acronyms and initialisms are more likely to use full stops if they are written in lowercase letters (m.p.h.), but these, too, are often written without stops (mph); if full stops are used, they should be used after all letters in an acronym or initialism, not just the last one (‘m.p.h.,’ not ‘mph.’). Standard abbreviated forms for weights and measures generally do not take stops (‘m,’ ‘cm,’ ‘kg,’ ‘kph,’ ‘ms’ etc.). As a general rule, full stops are used less frequently in scientific contexts, but American English tends to use full stops more often than British English does, including in contractions (‘Mrs.,’ ‘Mr.’ and ‘Jr.’) and initialisms (‘U.S.A.’ and ‘R.E.M.’). When true abbreviations such as ‘vol.’ and ‘ch.’ are used as plurals with an ‘s’ at the end, they technically become contractions because they include the last letter, so, strictly speaking, they do not require a full stop, but one is generally used in any case for consistency with the singular forms (‘vols.’ and ‘chs.’). In an unusual abbreviation such as ‘c/o’ (for ‘care of’) the slash takes the place of the first full stop and the second stop is omitted (see also Section 5.6.5).