Big numbers (BANs)
A big aggregated number (BAN) is one value that delivers the key insight at a glance. It is the simplest visualisation there is.
| Use a big number when… | Don’t use one when… |
|---|---|
| The message is one number or fact | The reader needs several data points to understand the message |
| You want to show an outcome rather than a relationship | The insight lies in a comparison, distribution or composition |
| You want to break up dense text | You’d need more than three or four on the same page |
| The surrounding text can provide context |
Rules
Every big number has a label (what it is, including units and period) and a line of context.
Use them sparingly. Pick only the numbers that sum up the core message. A page full of big numbers is a table with bad formatting. The exception is the KPI row of a dashboard, which can hold three to five, each with a comparison.
Put them where the narrative needs them, usually at the start of a section or in the margin.
Making the number mean something
Readers understand a number better when it’s related to something they know:
- “Equivalent to X% of Y”
- “About the same as X”
- “Roughly X times higher than last year”
- “About one X for every Y”
Style
- Show the value in bold and large, in Black or Dark Teal, with tabular figures.
- The label and context line are regular weight and smaller.
- Use brand colours for the number and any accent. Up and down arrows may use the data colours, but always together with a + or − sign.
Barrio, Goldstein and Hofman (2016) found that “perspective” sentences like those above make numbers in the news easier to understand and remember. See references.