Using a spot matrix graphic to make comparison easier

Problem

The graph to the right was produced in Excel for a local Crime and Disorder Audit. It has many problems:

• More time was spent choosing the colours, which are a poor choice, and working out how to fade the background blue.
• The graph takes up a lot of space, but it is only showing the data for one crime type.
• Comparison against the various targets is difficult.
• Ordering the wards by A-Z is rarely a good idea as it does not make it easy to see the order of total crime by ward. Making the labels at an angle makes it harder to read.

Solution

In Edward Tufte's, The Visual Display of Quantitative Information, a similar graphic is used to show the faults in American cars. The design now allows for more data to be shown in the same space - six crime types over three years.

It is data rich and shows meaningful comparisons over time. Although there is a key in the report, all the viewer needs to know is that more orange means more crime. Rather than trying to make sense of crime figures ward by ward, decision makers can talk about overall trends and outliers, which contributes to an informed debate about what they should prioritise.

In the Know - Audit Commission February 2008

How we did it?

Using Wingding fonts in Excel to create the circles, and Microsoft Publisher to display the images.

How you can do it

http://chandoo.org/wp/2008/10/07/excel-radar-charts-replacement-spot-matrix-download-template/

Evaluation

Stephen Few's Redesign

Stephen kindly provided a variation that suggested some useful alternatives, including an heatmap approach using color intensity alone, rather than the various amounts of fill color in the circles. He also added a box around the totals, to emphasis these figures, which we incoporated into the orginal design (see above)

Stephen also suggested considering sorting the area by magnitude, such as by the value of the most recent time period. This will make the areas easier to compare. They could also be arranged to reflect the actual geography of the district.