saint_monkey

• Tue, 15:22: This tweet requires sense of humor 1.0 or greater: You have no sense of humor installed.
• Tue, 15:45: RT @Disalmanac: Today is National Chocolate Chip Day, the day we remember all the chocolate chips that died in the Great Cookie Wars.
• Wed, 06:39: You start out thinking that a pie chart might be a good idea, but they almost never are.
• Wed, 06:40: It's also funny that clip art people often use pie charts to show "charting" conceptually...
• Wed, 06:41: I find that pie charts aren't even the best way to display how much pie remains... So there you have it.
• Wed, 11:45: Jesus is not the answer if the question is "do we have enough cheese?" #JustSayin #OrIsIt?

In 1786, a Scotsman named William Playfair published his "Commercial and Political Atlas," which contained the earliest known examples of both a line chart and a bar graph. Not content to rest on those laurels, in 1801, he published his "Statistical Breviary" which included the first known example of a pie chart, which showed the geographic distribution of the Turkish Empire prior to 1896 1789.

Since then, there has been only one pie chart ever published that can ONLY be sufficiently displayed as a pie chart:



Seriously, in 1991, a study called "Displaying Proportions and Percentages," appeared in the magazine "Applied Psychology" that showed that the only mental problem that people could solve more quickly with a pie chart than with any other, is to visually determine if Thing A plus Thing B, were greater than Thing C plus Thing D. If Things A thru D are displayed as portions of a pie chart, people solved the problem ASAP, otherwise they were sometimes misled by the data. It seems we are wired to visually sum up chunks of the whole in order to determine which choices would be the most advantageous for us.

For any other type of comparison that might lead you to a pie chart (or a doughnut chart, or a "spedometer" chart, or almost any other rotating axis charts...) You can almost always portray the information more clearly as a stacked bar or stacked column.

None of this logic, however, does much to deter pie charts. In fact, we seem to collectively love them. People rabidly defend them. Think of clock faces. These are just pie charts, displaying a portion of a 12 hour time period. You'd think that if pie charts were so darn confusing, that digital faces would have completely eliminated the clock face by now... and look around... In fact, do a little experiment. Count the number of rotary phones you find, and compare that to the number of clock faces you see. Both were replaced by better technology at around the same time. The ten key took off, the digital clock face gained acceptance as well, but while you'll find analog clock faces, you just won't find a rotary style dial any longer...not even the ten key arrayed in a circle.

I think it comes down to the study mentioned above a bit... people love thinking they get a big chunk of something, so they gravitate to displays that show a chunk from a whole... They look at that and think, "look at that chunk. That's a big chunk. I want that big chunk. I want to BE that big chunk." Now, if we think of that chunk as pie... well hell son, who doesn't like pie? No real American would turn down pie.