Line styles

Use solid lines, dotted lines and dashed lines to differentiate between time series. This also means lines look more distinct when printed in black and white or if a user is colour-blind.

Axis labels and tick marks

For continuous data axes centrally align labels over tick marks.

For categorical data axes labels should be aligned between tick marks.

You can use more tick marks than labels; ticks indicate the scale or level of detail of the data.

Label the final tick if there are more ticks than labels and there is space to do so.

Economic inactivity rate for people aged 16 to 64
UK, January 1980 to October 2014

Legends or keys

A legend or key shouldn’t be used, instead label the data directly. If a legend or key is necessary, place it on the chart as close as possible to the data.

The order and orientation of the legend or key should be the same as the data.

Long category names

Use a horizontal bar chart rather than a vertical bar chart if your data has long category names.

Subcategories

If the subcategories are not the same in all of the main categories, label the main categories and subcategories directly on the y-axis.

Chart titles

In a statistical bulletin or report all charts should be labelled as a figure and numbered, based on the order in which they appear. Write the titles in sentence case. Be concise, noting the main axes of the chart, unless one of the categories is included in the subtitle. Include the geography and a time period in the subtitle.

Figure 1: Economic inactivity rate for people aged 16 to 64
UK, Dec 1980 to Oct 2014

Or

Figure 2: Number of unemployed persons by region
England, 1993

Chart labels

Chart text must be horizontal. If the labels won’t fit into the required space, transpose the chart or convert the units.

Unemployed adults age 16 to 64 by region
England, 1993

Unemployed adults age 16 to 64 by region
England, 1993

Right align y-axis values.

Pets by nation
UK, 2012

Labelling values in a chart

Bar charts shouldn’t need data value labels. If you need data value labels, create a chart−table combination.

If you can’t create a chart−table combination, make sure the data value labels are placed at the base of each bar and right-aligned.

Annotation and footnotes

Chart annotations can be very useful to highlight key messages in your data. They must be concise and relevant. Place annotations on the chart as close as possible to the data points of interest.

Avoid chart footnotes where possible. If extra information is needed:

  • annotate the chart
  • include the information in the statistical commentary accompanying the chart
  • add a footnote to the chart title

Number of divorces1
England and Wales, 1910 to 2011

Footnotes (include at end of accompanying copy text)
1 Divorce figures include both decree absolutes and decrees of nullity