Data Visualization

How to visualize data with extreme value differences?

I came across this visualization problem on a UX User Experience blog. [SOURCE]

Problem

I am working on some routines for a client application to visualize data in a 3D bar chart style. The data consists mostly of smaller values with only a few large values.

For example:

6,942,535,341
23,598
19,203
58,201 

So, the problem is that the large values pretty much makes the visualization useless. Does anyone have any suggestions on how to display this data … OR … perhaps a suggestion on how to massage the data to make it more visually appealing?

There were several suggestions made by other bloggers, but this recommended solution caught my eye.

Solution

For anyone mathematically inclined, the answer is to use a log scale.

For non-mathematical people, you may be better off showing a break in the chart and then the extreme value.

log scale

Here are a couple of the responses to this proposed solution.

  1. As much as I hate to downvote, I really don’t think the ‘non-mathematical’ option is a good solution. It’s more misleading than helpful, as the mind’s got a pretty powerful inclination to compare the bars without taking the axis break into consideration. In such a situation, a simple table of numbers might be better, as you’ll instantly see that some values are much wider than others. – Mal Ross Mar 20 at 21:29
  2. @MalRoss it isn’t always about comparing all the values with each other.  Sometimes it’s more about visualising the relationships between a lower group and a higher group.  And in terms of reading charts vs. tables, charts give a much quicker overview, and so are often preferred in business. – JohnGB Mar 20 at 22:08
  3. Logarithmic scales are probably the best bet, though they still end up throwing off the true vastness of the difference.  It really depends on what needs to be conveyed by the way that the information is displayed.  If the vastness of the difference is of key importance then simply graphing the small number as a very small line may still be appropriate.

03/26/2013 – Here are some thoughts from Alberto Cairo, The Father of Infographics.

Alberto Cairo Comments

Finally, one responder simply provided a cartoon to state his point of view (shown below).

What do you think about the solution proposed above? I have had this problem in the past too and would love to hear your point of view.

Regards,

Michael

log_scale

1 reply »

  1. I’d prefer the cartoon, or in any form a graph that lets the ‘outliers’ go beyond the boundaries of the graph. That makes the point of the extremes the best.

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