I saw this treemap for the first time a few days ago when I read Bryan post.
They were too many reasons to redesign that graph, I will not repeat them all here.
Bryan redesign does a great job. He uses horizontal bar charts to encode years of lost life, % of change and, as a bonus, a third measure, all of them providing a much better interpretation than existing treemap. A treemap visualization usually serves for: grouping, part of a whole ratio - within group and global - and uses to encode an extra measure using colors. Comparison between lengths of bars sharing the same baseline will always be more accurate than comparison between areas, situation becoming even worse when the ratio width/height of the comparing rectangles is very different. More than that, the colors intensities encode very poor the % of change information. Bryan again uses bars to encode accurate that information. Eventually he is using colors for grouping purposes only, dropping any intensity variation making the whole design pleasant and effective.
Ignoring the unnecessary 3D effect of the original design, I could not see how Bill Gates could see at a glance "that while the number of people dying from communicable diseases is still far too high, those numbers continue to come down". Especially the second part of his statement. So I decided to come up with my own version using Bryan colors, labels and values using a different approach. My design is trying to be a reinterpretation of the original treemap goals, starting from the original remarks and Bill Gates comment. Here is my version:
Bellow I use YLL as abbreviation for years of lost life.
Shapes height encodes the part of a whole absolute percent of YLLs. They are ordered in Y direction in the descending order of YLLs for groups and elements within the groups.
Shapes Y position encodes the cumulative percent of YLLs
Shapes X position (center) encodes the other valuable measure (% of change of YLLs).
My solution improves the original solution in the following aspects:
1. The design tells the story.
2. Improved visual approximation of part of a whole for groups and elements (precise percentage is specified).
3. Improved visibility for % of change YLLs. See (almost) in block progress of the gray group (see Bill Gates comment).
4. Because the shapes do not overlap, useful information can be added for "relevant" elements (if height of available space is enough to fit the text)
5. Shapes are rendered top to bottom within group in the descending order of YLLs, allowing an easier comparison. Using bar heights only for comparison is easier then comparing different width/height ratio rectangle areas.
6. Colors are used just for logic grouping, dropping distracting intensities.
7. Design is very compact, being suitable for any web site or magazine article.
8. Solution is also suitable for animation starting from an stacked block horizontally centered in the graph.
1. Possible confusion in decoding shapes width. They do not relate to the % of change, but neither a bubble graph does relate the diameter to any of the axis scales.
2. It looses accurate comparison between elements. Still, it looks for me easier to compare (even not aligned) bar heights than the areas of the elements in a treemap.
My interpretation is that shape sizes are important more as order of magnitude than for precise comparison. Ordering them and mentioning (only the large) values next to the shapes do the right job IMO.
How does this work for you?