These words are frequently misused in Task 1 essays

  • Fluctuate
  • Figure
  • Rate
  • Peak

Their usage in a science/math context are detailed below.

There is also a list of types of tables and figures presented in Task 1 at the end.


Fluctuate = to vary with respect to a trend line. Fluctuations can be seen on line graphs. Tables or bar charts with discrete values do not have enough data points to clearly detect a fluctuation.

Fluctuations can be random or cyclical. The graphs below illustrate the concept of fluctuation.

Use the words "vary/variation" for general changes in data values. Most measured data values vary as a function of time.

2. Figure is a diagram, graph, chart, or table in a scientific article. In this context, "figure" is very very rarely used to mean a data value. It is frequently used in business reporting articles (newspapers) to refer to sales or profits. And in that context, it is usually plural.

3. Rate: A rate is not, in general, the same as percentage. A rate involves a division of two values; usually time is in the denominator. For example a rate of speed is (distance travelled)/ (time ). e.g. 40 km per hr.

So if you have a pie chart with percentages, or a line graph or stacked bar chart, do not use the word "rate" unless it is specifically defined in the data description, for example literacy rate, unemployment rate, interest rate or exchange rate.


This bar graph shows the percentage of households in owned and rented accommodation in England and Wales between 1918 and 2011.

There are no rates on this bar graph. However, you can get a good mark by deriving or calculating one from the data as shown in the rectangle below the graph.

The rate of increase in the percent of households that owned their homes between 1918 and 1991 was about 6.8% per decade.

4. Peak:

A peak in line graph has data both before and after the peak with lower values. If the highest value of a data item is at the beginning or end of the period, you cannot say it is a peak, because you do not have enough information. For example, there is a peak at 1981, but there is no secondary peak in 2011.

However, when you have more information, you can see a peak in 2012. If the graph covered only the period 1995-2015, you can say there is a peak in gold prices at 2012.

Types of Graphics in Technical Writing (Source: )

I have not encountered any Gantt Charts, Org Charts, Photos, Animations of Film clips in IELTS Task 1 samples, but maps (not on this list) are included. The common description "Bar Chart" is not listed in this table, but it is good.

Maps are in the category of Illustrations.

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