Datavis tweeted about a fun chart he found comparing ‘kills’ between the top animals – I’m not sure the data are meant to be real or what ‘kills’ means, but the point is made that humans are by far the worst offenders. Part of the emphasis is that the human number is literally ‘off the chart’.
It got me thinking about how to show data like these – where you have one very large number and other much smaller numbers. There are two things that people may want to know- how much bigger the single point is than the others, and then how the others compare. I’ve thrown together a few ways you could do it:
Top left: default scaling – it certainly gets the point across that one value far eclipses the others, but you can’t really compare the others, or put numbers to them.
Top right: log scale – often espoused as a solution, but frankly I can’t stand it. Most people don’t get log scales, and I find myself looking to the axis to compare values – I may as well just have the values in a table. It’s also difficult to compare small differences between bars.
Middle left: breaking the axis – you can’t really visually see how much bigger the human contribution is, but the point is made that it’s much bigger, and you can still compare the smaller values. There is no way in Excel to do this automatically – you can limit the axis max of course, but there’s no indication that the bar continues upwards.
Middle right: two charts – Arghhh, my eyes, a pie chart and some bevel effects. Actually I quite like this – pie charts are fine for comparing two values if you’re not trying to read the exact comparison from them, though the numbers are needed. As for the bevel effect – I blame that on the excesses of Thanksgiving..
Bottom left: aspect ratio – simply enough, make the chart so long that you can compare the smaller values. Even on web only presentation this is a difficult one because of the real estate used up – that is, unless you use this space for other content.
Bottom right: just imply a continuation – similar to the broken axis, and similar to the original chart that Datavis tweeted, but with the actual value shown. Needless to say, this is not a default view in Excel..
Any comments on these, which is your favorite? How would you address this challenge for a dashboard vs. print publication?