Post on 31-Mar-2015
transcript
THE CHART CLINIC
CHARTS NEED HELP.
WON’T YOU HELP THE CHARTS?
LAUREL HYATT, 9 JUNE 2013
© Laurel Hyatt
BAR CHART DO’S AND DON’TS
Do:
• Make the Y axis 0 if possible
• Show scales (such as years) in even increments
Don’t:
• Use more than about 10 bars per chart
• Use more than about three sections in stacked chart
• Be too precise with number labels
• Turn a time series into line chart if years are missing
WHEN A BAR CHART SHOULD BE SOMETHING ELSE
When you have… Instead of a bar chart, you should use..
Too little data Text
Too much or very precise data Table
Even-year time series Line chart
Parts of a whole (percentages add to 100%)
Pie chart
LINE CHART DO’S AND DON’TS
Do:
• Use a scale that clearly shows changes over time
• Use even increments of time
Don’t:
• Use too many lines
WHEN A LINE CHART SHOULD BE SOMETHING ELSE
When you have… Instead of a line chart, you should use…
Uneven increments of time Bar chart
Too many lines Bar chart or table
Not enough variation in data over time
Table or text
PIE CHART DO’S AND DON’TSDo:
• Use pie charts to show parts of a whole
• Make multiple pie charts proportional in size
Don’t:
• Use fewer than three or more than about six slices
• Use more than one pie to compare apples and oranges
• Use slices that represent 0%
WHEN A PIE CHART SHOULD BE SOMETHING ELSE
When you have… Instead of a pie chart, you should use…
Too many slices Bar chart or table
Too thin slices Bar chart or table
Only two slices Text
Changes over time Line chart
PICTOGRAPH DO’S AND DON’TS
Do:
• Get creative when the audience and subject matter warrant
• Use proportionate size to indicate data
Don’t:
• Use a pictograph just because it looks cool
• Use three-dimensional objects to represent anything except volume
WHEN A PICTOGRAPH SHOULD BE SOMETHING ELSE
When you have… Instead of a pictograph, you should use…
Very technical or serious audience or subject matter
Chart, table, or text
Wide variation in size of data Chart, table, or text
Data that must be shown precisely
Chart, table, or text
Geographically sensitive data Something other than a map
FURTHER RESOURCES
“Save the Pies for Dessert,” by Stephen Few [e-newsletter article, www.perceptualedge.com]
How to Lie With Statistics, by Darrell Huff [book]
The Visual Display of Quantitative Information, by Edward R. Tufte [book]
Making Data Meaningful, United Nations Economic Commission for Europe [e-book series online]
Statistics Canada’s Learning Resources: Power from Data! www.statcan.gc.ca
http://flowingdata.com
http://ilovecharts.tumblr.com