The most common mistake presenters make with visuals is overloading them, says Judith Stein, co-author of Presentations for Decision Makers (Van Nostrand Reinhold, 1996).

When using visuals, "You want the audience to look at the screen, quickly get the message, and then focus on you," she says. When viewers have to spend time reading, "you become the voice-over to a video, and lose your effectiveness as a presenter."

In visual support, Stein continues, "The operative word is 'support.' Visuals are supposed to support or aid you in giving the presentation - not replace you."

Simplify Data

Stein and her partner, Marya Holcombe, train business presenters through their consulting firm, Strategic Communications, based in New Haven, Connecticut. They advise presenters that planning a presentation involves two phases:

Solving the problem.

Analyze the audience, organize the data, and decide what message to convey.

Developing the presentation.

Choose the form and substance of each visual to best communicate the message. One form is the text, or word-only, visual, which serves as a roadmap to guide the audience through a presentation. The text visual is rapidly giving way to the conceptual visual, which uses a picture or design to convey an idea.

But the real workhorse of most presentations is the chart or graph that shows relationships among variables; this form enables the audience to grasp complex data at a glance.

"You create charts to help you see what's happening," Stein says. "The tendency is to grab these charts and use them in the presentation, and most of the time doing this doesn't work."

Assume, for example, that you chart sales, manufacturing costs, administrative costs, operating income, and earnings for the past seven years. In the process, you discover that administrative costs have risen faster than manufacturing costs over the past three years - an important message. You should then abandon the earlier chart in favor of one that compares only the two costs in the shorter time span.

"The chart you make in solving the problem may not be the best chart to convey the message," Stein says. "You have to pare the ideas down and simplify."

Make Charts Communicate

Simplifying a chart often requires changing the chart form - switching from a line graph to a horizontal bar chart, for example, because it communicates the message more effectively.

How do you know when to use which chart? That depends on how well you've stated the message, says Stein.

Too often, a presenter makes the mistake of putting a label, such as 'Sales 1990-1995,' at the top of a chart. "Your heading should always tell people what you want them to look for on a chart. An action statement or message will do that for you." An action statement has a verb and is a complete sentence, such as"Sales reverse downward trend except in West."

Choosing the Chart

Once you have an action statement as a heading, look at the verbs in the statement to get an idea of the best chart to use to present your data.

Showing change over time.

Look for a key word such as "grow," "decline," or "trends." If, for example, you want to show how college entrance test scores have changed over 30 years, use a line chart. Line charts are best when a variable has more than four or five data points, and you want to emphasize continuity over several months or years. The slope of the line tells viewers in a glance the direction of the trends.

However, if you have fewer than five data points and you want to emphasize quantity at discrete times - for example, how administrative costs have risen faster than manufacturing costs over three years - use a column chart (vertical bars). Since the audience naturally associates left-to-right with the movement of time, vertical bars work better than horizontal bars for time series data.

Comparing items at one point in time.

Look for a key word such as "ranks" or "compares." If, for example, you want to show the highest profit, the lowest interest rate, or the most products sold, or you want to rank variables from largest to smallest, use a horizontal bar chart.

Bar charts are often the best way to compare a set of individual items or several sets of related items. The bar's length corresponds to its ranking; the bar's label identifies the item.

Comparing parts of a whole.

Look for key words such as "percentage," "portion" or "share." If, for example, you want to show the proportion of state government budget spent on education, use a pie chart. However,the number of pie slices should not be more than five, and each slice should be easy to see and interpret.

A pie chart is best when you want to highlight one part of the whole. Place this component in the 12 o'clock position and "explode" it out of the pie for emphasis.

When you want to show relative proportions of two, three, or four wholes, a segmented bar chart may work equally well or better. In this chart form, each bar represents 100 percent, and each segment a percentage. A series of vertical segmented bars shows how percentages change over time.

Comparing data by geographic location.

Look for key words such as "country" or "state." If, for example, you want to show sales by region, use a map. Distinguish among regions by using different colors, shadings, or symbols.

Other commonly used forms include the organization chart (which shows functional relationships in a group or structure), the flow chart (diagram of process), and the Gantt chart (which shows the duration of different tasks across a calendar span).

Making these simple charts - as well as more complicated forms - has become considerably easier with presentation software. With a few keystrokes, the user can change bar width, color, type size, and other elements.

However, presenters should resist the temptation "to use every bell and whistle," says Stein. "Don't let the artistic possibilities interfere with the message."

Strategic Communications offers the following guidelines for designing visuals, regardless of whether they are overhead transparencies, slides, or computer images.

  1. Convey one message per chart. Make the message the heading.

  2. Make the chart easy to read. Label the X and Y axes and label the lines, bars, or pie wedges. Make the most important text largest, the most important data lines or sections darkest.

  3. Be accurate. Always start a numerical axis at zero. Compare only like variables.

  4. Eliminate all unnecessary details. Avoid grid lines, data points, boxes, and other devices unless they relate to the message.

  5. Use no more than four colors per visual.

  6. Avoid vibrating fill patterns, such as contrasting lines, wave patterns, and crisscrosses.

  7. To focus attention, use color, shading, or images such as arrows to highlight key words or concepts.

  8. Write in upper and lower case. Words written in all capitals letters are hard to read.

  9. Make bars and columns wider than the spaces between them.

  10. Use presentation software sensibly. When necessary, adjust the default mode to simplify a visual.

Strategic Communications offers a set of diskettes for Apple Macintosh and IBM-compatible computers, providing examples of effective charts and conceptual visuals in PICT and Microsoft PowerPoint format. The diskettes are available by ordering directly from Strategic Communications, at a cost of $49.95 plus shipping and handling.

Bar Chart Horizontal bar chart

Line Chart Line chart

Column Chart Vertical chart

Pie Chart Pie chart

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