Designing & Using Charts & Graphs Compiled by: Jim Lucas Modified by: Luke Reese Franklin (42-48, 91-96, , , )

Overview After this presentation, you should better understand:  Using the right chart or graph to present your information  Design principles for charts and graphs  How to lie and cheat with graphs, numbers and statistics

Use the right tool Percentage and Proportion Pie, divided bar chart RankingsVisual table, bar or line graph Cumulative totals Layer or stacked graph Value, time, space relationships Diagram, chart, or map

Pie charts Pie is based on 100% Slice represents relative amount of a whole Slices should be percentages—not absolute values Good design:  Easily distinguished pie slices  Largest slice starts at 12 o’clock and continues clockwise  Slice size decreases clockwise around pie  Label the pie directly

Things to avoid on a pie Exploding all the slices Inconsistent labeling Legends No labeling

Pie Chart Figure 1. Michigan’s Economy

Pie Chart Figure 1. Industry Contribution to 2007 Michigan’s Economy

Proportional bar chart Used to show proportional amounts as a pie chart Use side scale for more precise measures Make it wide enough to read If you have multiple bars, put the least varying factors first

Pie Chart Figure 1. Industry Contribution to 2007 Michigan’s Economy

Bar charts Use to show change in ordinal (ordered sequence, e.g., 1 st, 2 nd, 3 rd ) or nominal (name or form, e.g., Yahoo, Google, Ask.com) data Usually vertical, but use horizontal if it makes sense Color code consistently Avoid over emphasizing one line If you use a legend, have it follow the order of your bars

Figure cattle loss percentages by cause Figure cattle loss percentages by state

Line graphs Used to show change in trends and continuous data Vary color or line weight to call attention to specific points Points on the line are important for precise values Be consistent with labeling

Line graphs continued Put warm, bright colored lines on top Use a scale that accurately reflects the change in information

Figure 4. Currency Exchange Rate (US$ to NZ$ and AU$) for first day of month, 2006

Picture chart or graph You can use pictures in the place of a bar chart or graph Follow color and theme conventions Have the pictures align in the same direction Vary size not color or shading

Palm Tree Growth

Tips for diagrams and maps Follow the culture of the information Identify relationships on a chart Use color, line weight, shading to organize information Show only relevant information Avoid gridlines unless needed

Organizational charts Squares or rectangles to indicate divisions Top down structure Solid lines - direct relationships Dashed line - indirect relationships

Organizational Chart Administrative Assistant Staff Faculty Assistant Chair Specialists Technology Manager Information Officers Communications Manager Department Chairperson Figure 5. Departmental organizational chart, February 2008

Figure and Table Labels Very important Number each figure sequentially Place label under chart in same location (repetition) Provide a title Provide an informative caption to identify the purpose or meaning All figures must be referenced in the narrative Figure placed as close as possible immediately after the narrative reference

Lying with graphs Altering the y-axis Distorted shapes Uneven start point Using color, lines or other technique to distort differences Using 3-D effects or distortions

Michigan’s Economy

Lying charts and statistics Percentages and absolute values Numbers are relative Squishy numbers and figures Value labels Error

Absolute values Number of cattle deaths attributed to coyotes N Montana2,000 Michigan40

Absolute values vs. percentages Cattle deaths attributed to coyotes N% of total deaths Montana2,00010% Michigan4020%

Relativity Cattle deaths attributed to coyotes over 5 years N% of total deaths Montana2,00010% Michigan4020%

Relativity II Cattle deaths attributed to coyotes over 5 years NMonetary Loss% loss of total sales Montana2,000$5009% Michigan40$30020%