Election chart junk – 3D column graph
Croatian parliamentary election 2011 is over. In all media now it is time to explain the results and to visualize statistics and quantative values. We can see various graphs on TV or in newspapers. Unfortunatelly, only small portion of those graphs are really explanatory with insights and scientific precision. For example, today I can read about number of seats in parliament won by each party. They are “explaining” quantitative value, number of seats, by this graph (this is photo taken from newspapers, thus lower quality):
I really don’t know where to begin with my critics. First of all, 3D column -or bar – graphs are never a good choice to visualize category comparisons. But yet, it was chosen to do the job. Secondly, the author selected 3D graph with perspective which was totaly without any reason. That means that I, the reader, am forced to compare in perspective meaning that I have to take into account that what is closer to me may appear bigger, but can really be on absolute level smaller!
Let us move on: there is no scale whatsoever on those graphs. Let’s make this graph easier and let’s name parties A, B, C and D:
Notice how 2 seats for B are not twice as big as 1 seat for C or D! 10 seats for option A apper to be only about twice as big as B (2 seats) and so on…
So many mistakes in just one graph. The only worse case will be if author omited explicit numbers of seats, then this graph will be totally useless.
When we want to visualize category comparisons like in this case, we use bar or column graph, without and 3D effects, perspective corrections or other misinformative actions. Period. I even do the right type of graph faster then the wrong one: