Only a graphic can display a large volume of data in a small space.
The man who invented the bar chart, William Playfair, was skeptical about his invention, noting that his bar chart did not chart the progression of time. Multiple bar charts can be used, but generally, a graphic is a better way to display data that evolves over a timeline.
A good graphic includes every relevant variable in it - instead of looking at multiple graphics and trying to compare the two, all the relevant information should be laid out before the viewer in a neat and accurate fashion.
Graphics that accompany data should either be to scale or not used at all.
Lie factor:
size of effect shown in graphic
over
size of effect shown in data
Compare apples to apples.
Don't have a misleading zero point.
Draw everything to scale.
Tables are usually better than graphics for reporting 20 numbers or less.
Use as little ink as possible.
If the ink isn't displaying data, erase it.
The idea that statistics are boring has created a dearth of graphical abominations to accompany them.
Japan's statistics story:
No nation ranks more highly in its collective passion for statistics than Japan. Statistics are the subject of holidays, conventions, awards, and nationwide contests. Entries in the children's statistical graph contest were screened three times by judges, who awarded first prize this year to the work of five seven-year-olds. Their creation, titled "Mom, play with us more often," was the result of a survey of 32 classmates regarding the frequency with which mothers play with their offspring and the reasons given for not doing so.
When color is used to portray varying degrees of strength within the same data set, gradients in color, not multiple colors, should reflect the strength of the variation.
A small graphic, if it's to scale, is absorbed with little loss of information.
Tables > pie charts. Graphics > pie charts. The only thing worse than a pie chart are multiple pie charts.
When numbers are highly labeled, a way can be found to work the labels into the graphic.
The text relevant to a graphic should lead into the graphic. Don't just slap the graphic anywhere on the page the way magazine editors do.
The seperation of blocks of text from their accompanying graphics is a deevolution caused by advances in printing technology.
Outsourcing the art for your data is ill-advised, because commercial artists are usually better cosmeticians than they are analysts.
Display data with greater weight in thicker lines.
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