The matter of bad choice
Oct 28, 2008
Right on the heels of the disastrous bubble chart comes another, courtesy of the NYT Magazine. Bubble charts are okay for the conceptual ("this is really big, and that is really tiny"). This chart wants readers to compare the sizes of the bubbles, which highlights the worst part of such graphs.
Poor scaling is the huge issue with bubble charts. They are the prototype of what I call not "self-sufficient" charts. Without printing all the data, the chart is unscaled, and thus useless (see below middle). When all the data is printed (as in the original, below left), it is no better than a data table.
In the above right chart, we simulated the situation of a bar or column chart, i.e. we provide a scale. For this chart, the convenient "tick marks" are at 10, 20, 34, 41. Unfortunately, this scaled version also fails to amuse.
Note further that the data should have been presented in two sections: the party affiliation analysis and the gender analysis. Also, it is customary to place "Independents" between "Republicans" and "Democrats" because they are middle-of-the-road.
A profile chart is an attractive way to show this data. Here, we quickly learn a couple of things obscured in the bubble chart.
On the issue of abortion, Independents are much closer to Democrats than Republicans. Also, there is barely any difference between the genders, the only difference being the strength of support among those who want to legalize.
Reference: "A matter of Choice", New York Times Magazine, Oct 19 2008.
PS. Based on RichmondTom's suggestion, here are the cumulative profile charts.
Bernard L. suggested a "tornado" chart: