Data visualisation and storytelling

The span of absolute judgement and the span of immediate memory impose severe limitations on the amount of information that we are able to receive, process and remember

George Miller

We, humans, ingest data through our eyes. If you work with data analysis, you know how important dashboards are. A user-friendly visual representation of complex data is important for effectively communicating insights to various stakeholders. A vast availability and development of data visualisation tools would help us to reduce friction in consuming the data.

However, cognitive overload is an important consideration in good chart design.  Users can easily forget information that is not presented in a clear and easy-to-use format. A cluttered interface can lead to visual and cognitive load overload, making it difficult to perceive information and make decisions. This is why it is important to create visualisations that help the user remember key data and quickly access it.

Cognitive psychologist George A. Miller in his article The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information (Psychological Review, 63, 81-97) argued that an average human mind is able to perceive 7 (plus or minus 2) elements without additional effort. This principle, known as Miller’s Law, has significant implications for data visualisation: it suggests that visualisations should aim to keep the information presented within this limit to avoid overwhelming the viewer.

An ideal dashboard should display between 5 and 9 pieces of data

When there are more than 9 pieces of data, you should use chunking to make the use of the data in short term memory easier. Keep it simple: focus on displaying the most critical data points and metrics in a dashboard first. After you have built an initial dashboard, test and iterate with users to collect feedback and make improvements to the visualisation.

This is the first article in the series about data visualisation and storytelling.