Numbers
WHO house style includes specifications about using numbers in text. Here are a few excerpts from the WHO Style Guide that cover common questions.
- Spell out whole numbers less that 10; use figures for 10 or more. However, if a sentence begins with a number, spell it out.
- The physician saw six patients on Friday, for a total of 15 that week.
- Twenty of the 60 samples tested positive.
- Use figures with units and unit symbols and abbreviations.
- The health clinic was 3 km from the village.
- Samples were collected on day 3 of the study.
- See Chapter 5 for more information.
- Write non-decimal fractions in words; do not hyphenate (two thirds of the village exhibited symptoms).
- Write dates as day, month, year, with the month spelled out in full (15 June 2010).
- Use figures to specify decades (The first case of HIV/AIDS was reported in the 1980s).
- Express measurements in SI units (the “metric system” – consult the SI brochure for details).
- Use numbers and the percent symbol to express percentages (not the words per cent).
- The rate of road traffic fatalities has increased by 15%.
- Use the 24-hour clock to express time of day.
