Other charts and maps Small multiple charts
Small multiple charts consist of two or more panels, each displaying the same type of chart but with different data.
This approach allows multiple data series to be presented more clearly than if all series were displayed on a single chart. Individual trends are clearer and reduce the reliance on colour for interpretation.
Small multiple charts can be created with various chart types but the most common are line charts and bar charts.
They are sometimes called facet or facetted charts.
Visual styles for small multiple charts are detailed in our chart style guide on Notion (opens in a new tab) .
Example of a small multiple chart
Small multiple charts are not currently available in the Office for National Statistics (ONS) chart builder tool. If you’re interested in using a small multiple chart in your publication, please let us know during the content support meeting.
When to use small multiple charts
Consider small multiple charts when there are too many data series for a single chart to effectively display.
For example, if a line chart has too many overlapping lines, converting it into a small multiple line chart can make each trend easier to follow.
Example of a cluttered line chart with overlapping lines
Example of a small multiple chart showing the trend of each category
Axis scale
Make sure that each panel within a small multiple chart uses the same scale for both the x (horizontal) and y (vertical) axes.
If comparing a series of significantly different magnitudes, consider using an index or a derived variable. See the What data to include guidance (opens in a new tab) for more information.
Number of panels
Limit the number of panels in a small multiple chart to 12 or fewer.
Too many panels can make it difficult for users to scroll through and identify key trends, especially those on mobile devices.
Order of panels
Arrange the panels in a logical order that helps the user. See the Ordering in charts guidance (opens in a new tab) for more information.
Primary and secondary categories
Small multiple charts often display data for two sets of categories:
- categories represented by each panel (primary)
- categories represented within each panel by bars or lines (secondary)
It is easier to compare categories within each panel than across different panels.
Prioritise the categories that are most important for users to compare within each panel.
The following examples show values for males and females within different countries.
To focus on comparing values for males and females within each country, display these categories within each panel.
To compare values across different countries, display countries within each panel.
Example of a small multiple chart focusing on comparisons within countries
Example of a small multiple chart focusing on comparisons between countries
Providing context
Comparing precise differences between series in different panels of a small multiple charts can be difficult. To make comparisons easier, consider including reference data in all panels, such as a national average.
For small multiple line charts, consider adding a single line representing the reference group, or display all data lines in grey in the background of each panel.
For small multiple bar charts, include reference lines or dots to represent averages or other comparison values.
Annotations
Use annotations on small multiple charts to provide context but keep them concise. Consider using abbreviations and avoid unnecessary verbs.
If using annotation lines or bands, you only need to include the text labels on the first panel.