29 How to write numbers, units and abbreviations

General

This section provides some guidelines on writing numbers, units and dealing with abbreviations in scientific writing.

Numbers

In scientific writing the following conventions apply to using words (one, two, three etc) instead of numerals (1,2,3 etc) in passages of continuous text (i.e. not in tables, figures or footnotes).

Write out all whole numbers: smaller than 10 (zero-nine), all other numbers are written as numerals.

Exceptions

• Never start a sentence with a numeral; either write it as words or recast sentence.
• Numbers that are results of calculations or measurements appear as numerals.
• Values with units (1 minute) appear as numerals
• Two adjacent numbers: spell out one of them (twelve 3 m beams, twenty-three 10 g samples)
• Numerals are used when a number less than 10 appears in a range or list with higher numbers (‘4, 11 and 17’ not ‘four, 11 and 17’)
• Numerals are used for numbered elements of documents (Chapter 1, page 9).
• Hyphenate spelled out compound numbers (twenty-three calculations are required)
• If the numeral zero could be confused with the letter O, or the numeral 1 with the letter l, spell them out.

For more specific details go to

Units

Most style manuals recommend putting a single space between a numeral and a unit: 1 m (not: 1m).

Exception: there is no space between numeral and superscript-type unit symbol (10², 4ii, 15’)

However: when used as a measure of temperature it is recommended to keep the space (10 C).

Important: these guidelines are a matter of style preference. Select a style for your report and use it consistently.

Use the same symbol for singular and plural (2 kg not 2kgs).

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Abbreviations

Abbreviations (short forms of words, e.g. Am.E.), acronyms (words formed from initial letters of several words, e.g EU) usually require explanation.

1) The general rule is:

Write an abbreviation out in words when you use it for the first time, followed by the abbreviation in brackets, for example Lucerne University of Applied Sciences & Arts (HSLU); thereafter use the abbreviation.

Reader-friendly documents can repeat this principle for each new chapter provided you use abbreviations your potential reader is not familiar with.

2) When the abbreviation or acronym is widely understood (e.g., DNA, NATO), you do not need to write the full name but you can include it in the list of abbreviations.

3) Whether to use a or an before an abbreviation depends on the pronunciation of the first letter: a CD, a UN reporter saw an UFO, an ISBN, an SMI index result.

Commonly used abbreviations

Many abbreviations are widely used in documents and do not require a definition, such as:

• e.g. = for example
• et al.= and others
• etc. = and so forth
• i.e. = that is to say
• fig. = figure
• min. = minimum
• max. = maximum
• n.d. = no date
• p. = page

Days of the week and months are spelled out in the text, but in notes, figures, tables abbreviations can be used.

Writing the date: Using numerals can cause misunderstandings, such as in 2/8/2016, which can be read by Americans as February 2, 2016 or as 2 August 2016 by Europeans. Therefore, spell out the month.

Writing the time: write 9:00 A.M. or 9 am when using a 12-hour system, and 15:20 (15h20) for the 24-hour system. Add noon or midnight after 12:00 to avoid miscommunication.

Titles and degrees: Social title (Mr., Mrs, Ms.) are abbreviated when preceding a name (periods/ full stops can be omitted).

List of abbreviations (section)

• Alternative headings: nomenclature, abbreviations and symbols.
• Located: usually placed after the table of contents and the list of figures/tables.
• Usually (this is a recommendation) this list is alphabetical, uppercase letters are followed by lower case letters; at the bottom of the list of special symbols.