Pie charts can make you laugh

One of my favourite bloggers is Jessica Hagy. Each day she publishes an index card with a comical graph. Most pie charts are terrible but this one about "I'm fine." amused me.

Getting creative with Pie Charts

The Australian Securities Exchange (ASX) is a very successful organisation with an operating revenue of over $538 Million. However their success does not stop them creating strange pie charts. The following diagram is from page 35 of the ASX 2009 annual report.

The pie chart represents the number of referrals from the ASX to the Australian corporate regulator for possible breaches to trading laws or rules. The interesting innovation is the 'Total Referrals 88' which is the outer circle of the pie chart. Initially I thought this must represent the sum of the slices of the pie but the slices add up to more than 88. Then I spotted the asterisk indicating a single referral may contain more than one breach.

This pie chart should win an award for visual confusion. The total referrals number visually looks like it should equal the sum of the slices but it actually represents a very different number.