Kaiser of JunkCharts has posted twice in a couple days about some charts that compare the effectiveness of different profile photo topics, in terms of attracting a potential date. The article that led to the controversy is The 4 Big Myths of Profile Pictures on a site called OK Cupid. Kaiser posted first in Light entertainment, where his attitude was “who cares, really?”, but after receiving serious feedback, he revisited the charts in From light to heavy. I should note that Kaiser himself is quite a good Chart Buster.
There are a number of strange and wonderful charts on the dating site, but the one that led to this specific discussion is shown here.
The major controversy it that the horizontal X axis is not located at zero on the Y axis, but at the average effectiveness of 27%. A second issue is that vertical bars pretty much force category labels with hard-to-read orientations. If these are really a problem, then a horizontal bar chart with the bars starting at zero solves it, as Kaiser demonstrates.
If you are interested in relative effectiveness of each photo category, then the zero axis origin may not be so important. Also, the resolution of this chart is better than if the bars had to start at zero.
This is an improvement in terms of legibility of labels and judging the absolute values of the bars. Perhaps a dot plot is equally effective?
Unlike a bar chart, starting the value axis at a value greater than zero poses no cognitive issues. We can then expand the scale, to gain back the resolution of the original chart.
What do you think of these alternatives?