Data-Ink Ratio

Definitions

The Data-Ink ratio is a concept introduced by Edward Tufte, the expert whose work has contributed significantly to designing effective data presentations. In his 1983 book, The Visual Display of Quantitative

Data, he stated the goal:

Above all else show the data

Tufte, 1983

A large share of ink on a graphic should present data-information, the ink changing as the data change. Data-ink is the non-erasable core of a graphic, the non-redundant ink arranged in response to variation in the numbers represented.

Tufte, 1983

Tufte refers to data-ink as the non-erasable ink used for the presentation of data. If data-ink would be removed from the image, the graphic would lose the content. Non-Data-Ink is accordingly the ink that does

not transport the information but it is used for scales, labels and edges. The data-ink ratio is the proportion of Ink that is used to present actual data compared to the total amount of ink (or pixels) used in

the entire display. (Ratio of Data-Ink to non-Data-Ink).

Good graphics should include only data-Ink. Non-Data-Ink is everywhere where possible to be deleted. The reason for this is to avoid the attention of viewers of the data presentation to irrelevant elements.
The goal is to design a display with the highest possible data-ink ratio (that is, as close to the total of 1.0), without eliminating something that is necessary for effective communication.

Example

This is an example of a graph with a low Data-Ink Ratio.

Low Data-Ink Ratio

The border around the graph, the background color and the grid lines are all unnecessary data ink.

Now an example of a graph with a high Data-Ink Ratio

High Data-Ink Ratio

We have deleted the border around the graph, the background color and the grid lines and drowned the attention to horizontal scales that are data-ink. There is nothing else to distract and the key features of the data stand out clearly.

Critisicm on Tufte's principles

Inbar, et al, evaluated in 2007 the people's acceptance of the minimalist approach to visualize information. Therefore he asked 87 students to rate their preference for two different graphs displaying identical information - a standard bar-graph and a minimalist version. Both versions were taken from [Tufte, 1983]. [Inbar, 2007]

The results showed that the majority students did not like Tufte's minimalist design of bar-graphs - instead they seem to prefer "chartjunk". [Inbar, 2007]

Bibliography

[Hunt, 1997] Neville Hunt. Data Ink. Created at: 1997. Retrieved at: October 25, 2005. http://home.ched.coventry.ac.uk/Volume/vol0/dataink.htm%7Cdate=November 2009Template:Dead link.

[Few, 2004] Stephen Few. Elegance Through Simplicity. Created at: October 16, 2004. Retrieved at: October 25, 2005. http://www.intelligententerprise.com/showArticle.jhtml?articleID=49400920.

[Tufte, 1983] Edward Tufte. The Visual Display of Quantitative Information. Graphics Press, Cheshire, 1983.

[Inbar, 2007] Ohbad Inbar, Noam Tractinsky, Joachim Meyer. Minimalism in information visualization: attitudes towards maximizing the data-ink ratio. In ACM International Conference Proceeding Series; Vol. 250. Proceedings of the 14th European conference on Cognitive ergonomics: invent! explore!, pages 185-188, London, United Kingdom, ACM, 2007