Visuals and technical communication Leading and misleading readers

Why use visuals? One good visual can replace a thousand words of explanation in technical communication As Edward Tufte says, “there are [data] displays that reveal the truth and displays that do not” (Visual 45).

What are the “right ways... to show data ”? Each type of chart or graph is better suited to displaying one type of data Select the display that most clearly illustrates your point

Select the right visual for the story Find in your data an intriguing point Never graph numbers just to include a visual Always make the visual accomplish something

Types of visuals Pie chart Line graph Bar graph Dot chart Table Map Photograph Line drawing Gantt chart

Pie chart Shows how a part or parts are related to the whole Data needs to add up to 100% for pie chart to make sense Figure 2.7 Collies, shepherds, and retrievers accounted for more than 70% of dogs placed at the shelter last year.

Line graph Line graph compares items over time, to show frequency or distribution or to show correlations Figure 2.8 Buster’s weight gain from six weeks to six months. He was born Jan 9. Source: King St. Veterinary Clinic medical records.

Bar chart Bar chart compares items, compares items over time, shows frequency, distribution, or correlation. Figure 2.9 Buster’s weight gain from six weeks to six months. Buster was born Jan. 9. Source King St. Veterinary Clinic medical records.

Dot chart Dot charts show correlation Show clusters of data so viewers can see relationships

Tables Tables display exact figures (when accuracy and detail are important) Table 2.11 Experimentally Determined Optimal pH of Micro-organisms OrganismOptimal pH S. cerevisiae E. coli 8.1 or higher L. plantarum 3.0 or lower S. aureus 8.1 or higher

Maps Maps show location or compare two items Figure A map shows the location of British Columbia in relation to the larger context of North America.

Photographs To reproduce exact detail or show something being used To show size. With extra large or extra small objects, include a reference point to illustrate the size. Figure The trees behind this totem pole illustrate the scale of the carving in downtown Victoria, BC.

Line drawings Figure 2.14 The digital photograph does not help users locate the birdbath contained within this waterfall design. Figure 2.15 The darkened areas of the sketch clarify for viewers the path of the water in the falls, as well as highlighting the location of the falls' birdbath.

Line drawings (cont’d) Line drawings emphasize specific details or show dimension They omit details that are irrelevant to your point

Gantt charts Gantt charts indicate timelines Used on proposals or progress reports to track stages of project

Conventions for using visuals A title All units labelled Source of the data Source of visual (if you didn’t create yourself)

Misleading visuals Conventions are sometimes subverted to obscure disadvantageous information Figure 2.17 Starting the x-axis at 100 in this graph exaggerates the number of women vs. men employed in these industries. This graph makes it appear that no women work in natural resources, which is not the case. Source: Statistics Canada, May 2006.

Adding visual interest can obscure the information Chart junk Figure 2.18 Sales figures for Sweetest Day are increasing steadily and expected to continue to do so over the new two years.

Use uniform-sized icons Use icons of a uniform size so units can be compared accurately in thousands (projected) $100 $200 $300 $400 $500