A Design Problem

I borrowed this example from a wonderful webcast by Howard A. Spielman Ph.D., which he did for DCI. He very consciously used it as an example of poor data presentation, specifically to illustrate the problems associated with tilting data graphics. This image was originally published in the book Visualization: Using Computer Graphics to Explore Data and Present Information, Judith R. Brown, et. al., John Wiley & Sons, 1995.

[Scroll down to see our solution to this graph's design problems.]
Design Example #7 Problem

My Analysis

This is a great example of two common problems:

  • Choosing the wrong type of graph.
  • Formatting the graph in a manner that obscures the data, in this case by tilting the pie charts to the left.

A Solution

In this case, we're primarily interested in tracking "who is gaining and losing market share and at what rate," so a line graph is the ideal solution. In addition to making changes in market share easy to see, this graph also makes it easier to compare shares of the market within specific years.

Design Example #7 Solution

As you can see, I've integrated a table into this display to provide precise values. Although this isn't always necessary, when precision is needed this approach provides it without cluttering the graph by displaying the values along the lines.