Identifying user needs

Before deciding to use a diagram, identify the user need. Consider if the user need can be met solely by clearly written text.

Questions to ask yourself

  • What is the message you would be trying to communicate with a diagram?
  • Would a diagram help the user to understand the subject or would it repeat what is already in the text? 
  • Can the message be communicated as text or a table instead of a diagram? 

If you have too much information to communicate, a diagram is unlikely to be useful to users. If you can describe the diagram in a short paragraph, use text instead.

When not to use a diagram

  • When your diagram raises as many questions as it answers. 
  • When there is too much text in the diagram – this can be difficult to read or scale for different devices. 
  • When the diagram is so complicated that it requires significant time and resource to create; the more straightforward it is, the more useful your diagram will be.
  • If the information could be organised as a table – this is a more accessible format.
  • If your content is updated regularly – it is easier to change text than it is a diagram.

If you are unsure whether a diagram would meet your users’ needs, contact the design team at ons.design@ons.gov.uk for guidance.

When diagrams meet the user need

Diagrams will meet user needs if they:

  • show a process or relationship without needing further explanation in text or footnotes
  • communicate information in a more succinct and direct way that can replace several paragraphs of dense text
  • can be understood by someone not familiar with the subject matter

Include alt-text for those unable to view the diagram.