6.4.5 Time

Although not as numerous as the various ways of expressing dates, methods for recording time in English vary and different forms should be used depending on the situation:

• As a general rule, words are used for periods of time such as ‘the trial lasted three weeks’ and ‘it took five months to repeat the experiment,’ but numerals are used for more exact measures (the trial lasted 17 minutes).
• Words also tend to be used for whole hours or fractions of an hour, in which no hyphens are needed: for example, ‘three o’clock,’ ‘half past four’ and ‘a quarter to eight.’
• When using ‘a.m.’ (ante meridiem for the time before noon) and ‘p.m.’ (post meridiem for the time after noon), ‘o’clock’ should not be used: ‘7 a.m.’ or ‘seven o’clock in the morning’ is correct, but ‘seven o’clock a.m.’ is not. Instead of ‘a.m.’ and ‘p.m.’ capitals can be used (‘A.M.’ and ‘P.M.,’ which are more frequent in American English).
• ‘Noon’ and ‘midnight’ tend to be more accurate than ‘12 a.m.’ and ‘12 p.m.,’ which can be confusing; if numbers are wanted, ‘12 noon’ or ‘12 midnight’ can be used.
• The 24-hour clock avoids potential confusion as well as the use of ‘a.m.’ and ‘p.m.’ because ‘12.00’ is noon, while ‘24.00’ is midnight, and ‘10.00’ is 10 a.m., while ‘22.00’ is 10 p.m. When the 24-hour clock is used, a full stop should be included in the number to avoid confusion with a year made up of the same numerals (‘the year 1130’ but ‘the time is 22.30’), and the same is the case with the 12-hour clock when minutes are included: ‘11.30 a.m.’ or ‘8.17 p.m.’); a colon is sometimes used (in North America, for instance) instead of a full stop (‘11:30’ or ‘8:17’).
• When referring to the length of time something takes, both hyphenated and possessive forms are acceptable – ‘a 45-minute drive’ or ‘a 45 minutes’ drive’ – or the information can be phrased using ‘of’: ‘a drive of 45 minutes.’

6.4.6 Currency

Currency can be expressed in words alone or using a combination of a word and a numeral, particularly when the amount is a round number below the word/numeral threshold used in a thesis: ‘four dollars,’ ‘six pounds,’ ‘eight euro,’ ‘4 cents’ and ‘7 pence.’ However, it is more common (especially for larger numbers) to record currency in numerals using the appropriate symbol before the numeral for ‘$45,’ ‘£25’ or ‘€35’ and after it for ‘25¢’ and ‘50p,’ without any space between the symbol and the numeral in each case. If fractional amounts appear along with whole numbers, the form should be the same for all amounts – ‘$25.00,’ ‘$14.99’ and ‘$0.85,’ not ‘$25,’ ‘$14.99’ and ‘85¢’ – and the cent or pence abbreviation should not be used along with the dollar or pound symbol (‘$14.99¢’ and ‘₤13.69p’ are never right). For large amounts such as millions and billions, words, numerals and symbols can be combined: ‘£5 million’ or ‘€6 billion.’ The dollar symbol is usually interpreted as the American dollar, so if a different currency is intended, it should be specified (‘C$’ for the Canadian dollar, for instance, or ‘A$” for the Australian dollar), and if there is any chance of confusion, the American dollar can be specified as well (US$). For predecimal British currency (before February 1971), pounds, shillings and pence are used, with ‘£’ for pounds, ‘s’ for shillings and ‘d’ for pence (£8 2s 5d). The last two abbreviations in particular were traditionally italicised and followed by full stops (2s. 5d.), but this format is rarely used anymore. If you need to use historical terms for money in your thesis (‘guinea,’ for instance, or ‘groat’), be sure to explain these for your readers as you would any other specialised terminology. For a helpful list of currencies of the world, see Appendix IX in Peters (2004).

6.4.7 Number Ranges

To record a range of numbers, words can be used along with the numerals: ‘from 1100 to 1300’ or ‘between 1100 and 1300,’ with the latter slightly less precise. Alternatively, an en dash (–) can be used without spaces between the relevant numerals (1100–1300), but the two systems should not be combined in a single range: ‘from 1100–1300’ and ‘between 1100–1300’ are incorrect. Technically, using a hyphen instead of an en dash in such ranges is incorrect as well, but a hyphen is often recommended in guidelines and is therefore acceptable in such contexts: do be sure that either the en rule or the hyphen in used consistently in all number ranges throughout your thesis, however (for more information on the use of hyphens and en rules, see Sections 5.2 and 5.6.4). Spans of numbers such as continuous page numbers are often elided to the fewest digits possible – for example, ‘34–5,’ ‘156–67,’ ‘1781–845’ and ‘1781-2’ – but numbers beginning with a multiple of ten are sometimes not elided (‘40–49’ and ‘500–507’) and in American English page numbers are often uniformly elided to the last two digits unless more are required: ’34–35,’ ‘156– 57’ and ‘1496–99.’ When eliding inclusive numbers containing commas, all numbers to the right of the comma are usually retained: ‘9,854–867.’ To refer to events that occurred between two years, a multiplication symbol is often used (1567 x 1573), and to indicate a year that stretches over more than one calendar year, a slash is used (2014/15) with an en dash linking a span of years using this format on one or both sides: ‘2012/13–2014/15.’

It is acceptable, however, to preserve all digits in number ranges (some universities, departments or thesis committees will even prefer this), and in certain contexts it is essential that elision not be used. Roman numerals should not be elided, for instance, and neither should Arabic numerals used in titles and usually in headings, the vital dates of people, date ranges that cross a century boundary (1197–1203) or BC dates because of the potential for misunderstanding (‘134–25 BC’ might be either ‘134 BC to 125 BC’ or ‘134 BC to 25 BC’), numerals combined with letters such as folio numbers using recto and verso abbreviations (folios 115r–117v) or dates with circa abbreviations (c.1575–c.1600), and the numerals 10 to 19 whether they constitute the entire numbers or merely the final digits (‘13–15,’ ‘116–19’ and ‘3915–18’). It is also best to avoid eliding numerals associated with measures because both ascending and descending scales can be used (so ‘22–8’ could mean either ‘22 to 28’ or ‘22 to 8’). Great care should be taken whenever numbers are elided because it is all too easy to produce incorrect or misleading elisions: for example, ‘1–300’ means ‘1 to 300,’ not ‘100 to 300’ (which should be ‘100–300’), and ‘23–9 November’ which could potentially be read as either ‘23 to 29 November’ or ‘23 October to 9 November’: in such cases, the full numbers are always better (23–29 November). Words should be used instead of en rules when the numbers are themselves written as words – ‘between five and eight years of age’ – and they are often better because less awkward than en rules in number ranges featuring other elements, such as the words in ‘28 November to 6 December’ (preferable to ‘28 November–6 December’), or in compounds that already use hyphens, such as ‘5- to 8-year-olds’ instead of ‘5–8-year-olds,’ although in this case rephrasing to use words only might be better (children between five and eight years of age). As always, clarity and consistency should be your goals.

PRS Tip: A professional proofreader may not be able to determine whether all of the numerical data in your thesis is correct – you as the researcher must do that, because you are the only one who has access to and a complete understanding of your data – but a proofreader can check, correct and provide advice on various important issues associated with numbers. He or she can ensure, for instance, that any numerical information appearing in more than one place in your thesis is always the same, that numbers are in all instances formatted in appropriate ways (in words or numerals, for instance, with commas or spaces and so on), that your use of numbers is clearly communicating your meaning and that those tiny errors that all too often tend to slip into numerical data are brought to your attention or corrected. If your thesis contains many instances of numerical data, you will certainly need to check all the data with the utmost care, but it will also be wise to have a second set of careful and critical eyes look over it, and the same is the case with other aspects of formatting in your thesis. PRS proofreaders are specialists in the use of effective headings, capitalisation, special fonts and abbreviations as well as numbers and will be delighted to help you polish and perfect these elements of your thesis.