31 Mar IELTS Task 1 Academic and PTE Describe Image: double/triple/quadruple/half
When talking about data in PTE or IELTS, it’s vital to mention obvious relationships between numbers, so we commonly use words like ‘double’ and ‘triple’.
However, we often see grammar errors when candidates use them. For example:
- The figure for China began at 6%, before it was doubled to 12.5% one year later.
- The number of men, at 90, tripled that of women, at 31.
Both of these sentences are incorrect and instead should be:
- The figure for China began at 6%, before it doubled to 12.5% a year later.
- The number of men, at 90, was triple that of women, at 31.
WHY? These words can be either verbs or adjectives.
When a graph or table shows change over a time period, we use the verbs double/triple/quadruple/halve to describe movement. The first three simply mean to increase by 2, 3, and 4 times respectively, while halve means to decrease by 50%. Like other regular verbs, depending on the tense or part of the sentence they are in, we can modify them with -ed or -ing. However, we don’t use them in the passive, so NEVER put is/are/was/were before them.
Look at the graph below showing movement and the example sentences:
- The figure for women began the period at 5000, with it doubling to 10000 two years later before falling to 8000 in 2014.
- The number for men was 3000 in 2011, while it rose to 4000 in the following year and more than tripled to 14000 at the end of the timeframe.
When a chart or graph shows a moment in time (no movement) and you want to compare categories, or you want to compare a point in time to an earlier one, we use the adjectives double/triple/quadruple/half (NOT ‘halve’). As they are fixed adjectives, we NEVER modfiy them with -ed or -ing. To make a comparison we put is/are/was/were before them.
For instance, in the graph above we can compare 2011 and 2013 for men:
- The figure for men in 2013 was 10000, which was more than triple that of 2011.
See the graph below for examples of clear comparisons between categories:
- Regarding Singapore, no qualification in science accounts for 60%, which is double the figure for school leaving exams at 30%.
- In terms of Malaysia, the percentage for school leaving exams is 35%, (which is) more than triple that of bachelor’s degree.
- The main difference between Singapore and Malaysia is bachelor’s degree, with the former standing at 20% and the latter being half this at 10%. (Don’t put ‘of’ after these adjectives)