Poor hospital
Today I read an article in an online ICT magazine that a Dutch hospital has chosen some web-based BI platform, of which I won’t mention its name, to measure performance. And even though I do support the hospital’s decision for a product that allows for visual performance analysis, I do regret however the fact the the visualizations that the platform offers are not always the most intuitive.
Currently I am reading the book “Now You See It: Simple Visualization Techniques for Quantitative Analysis” by Stephen Few, a guru on data visualization. This book is all about the fundamental principles and practices of quantitative data analysis. It explains why some data visualizations work better than others.
Looking at the visualizations the platform offers that the hospital has chosen, I believe there is some room for more intuitive visualizations. An example: the platform allows for 3D pie chart visualizations.
First of all, 3D is most of the times harder to comprehend than 2D, because the illusion of depth makes it harder to interpret the diagram (also, in 3D bar charts, the bars often hide bars that are in the background, so the may be hidden completely, causing you to overlook some potential vital information for your analysis).
Now for the pie chart, consider the following image, just randomly picked from the Internet:
The purpose of a pie chart is usually to compare data. Looking at this pie chart there are 2 things one can compare: angles and surfaces. But because of the shapes of the pieces of the pie, humans naturally have some difficulties evaluating the differences in size. You can see that the red area is probably a little bigger than the green area, but it is hard to determine how much exactly.
Most of the time when comparison is your purpose, consider using bar charts. Look at the image below (also picked randomly from the Internet), comparing bars is much easier. Especially if the bars are ordered by size, and not alphabetically by the name of their labels.
As for the hospital, I generally feel that the user interface of the product they’ve chosen is too busy, too distracting from the actual visualizations. I really hope that they are able to get the ‘aha’-moments they seek with this product.
