| The Gettysburg Address on
What Lincoln really said: But, in a larger sense, we can not dedicate we can not consecrate we can not hallow this ground. The brave men, living and dead, who struggled here have consecrated it, far above our poor power to add or detract.
From www.norvig.com/Gettysburg; courtesy of Peter Norvig.
I knew I hated PowerPoint, but it took Edward Tufte to help me understand why.
The moment when I knew, for certain, that I held a deep animosity toward the prepackaged presentations was several years ago when I met with the newly elected student government leaders on campus.
They were taking over an organization that was on the brink of making a real difference on campus they had momentum, energy, diversity and a plan. They were ready to share it with me.
And then they allowed the PowerPoint software to eviscerate their vision, reducing it to meaningless bullets and lists on slides that they proceeded to read aloud to me. The presentation sucked the meaning out of what had started as an important message, and the plan was reduced to a list of platitudes.
Weve all seen the same thing happen in professional talks that use PowerPoint software to organize information and show data. Good data get lost, or we are never able to determine their value. The lists of bullet points all look the same, with charts that plot a couple of data points against an unlabelled y-axis.
Four score .
Edward Tufte has been called the Leonardo da Vinci of data. He is the author of The Visual Display of Information, Envisioning Information and Visual Explanations: Images and Quantities, Evidence, and Narrative. His one-day courses, offered around the country, draw geologists, economists, biologists, politicians, marketing executives and many students. His message is that good content is critical for good presentations, but poor display of the information can kill great content.
During a workshop last summer (June 2003), Tufte observed that PowerPoint is a method of presentation that is corrupting serious thought. Most meetings with PowerPoint, he argued, result in detectable intellectual damage; the harm done to statistical data is enormous.
One issue is the loss of detail in PowerPoint graphics. For example, an average graph in Science has more than a thousand data points in it. A graph in The Wall Street Journal has more than a hundred. One in a newsmagazine such as Time might include 40. A typical PowerPoint graph (based on a study by Tufte of 28 textbooks on PowerPoint presentations) has 12 data points. (In 1982, the Russian newsmagazine Pravda had five numbers per graphic image.) As Tufte says, Serious data need serious graphics. PowerPoint doesnt measure up. Similarly, a typical PowerPoint slide has 40 words. An 11- by 17-inch paper handout can hold 30 to 50 times as many. Which is the richer presentation?
An example of the loss of clarity that comes with PowerPoint-imposed structure is how it was used to analyze the Space Shuttle Columbia disaster. Tufte describes it this way: in a PowerPoint festival of bureaucratic hyper-rationalization, 6 different levels of hierarchy are used to classify, prioritize, and display 11 simple sentences. The data, interpretation, conclusions and responsibility were all lost in a jumble of acronyms, modifiers and bullets.
Another issue is the homogenization of the presentation. Unless the user is vigilant, PowerPoint will reduce the content to the lowest possible denominator. The most dramatic (and entertaining) illustration of this is in Peter Norvigs take on Abraham Lincolns Gettysburg Address reduced to a PowerPoint presentation. For its full effect, imagine Lincoln muttering under his breath at the beginning: This didnt happen when I practiced maybe Im going to have to reboot I should have gotten a Mac. As in my opening example with the students, PowerPoint can drain significance out of even one of the most eloquent speeches in the English language, making it PowerFluff.
A time and place for everything
PowerPoint is not worthless. There is at least one valid use for PowerPoint as a slide projector, a holder of relatively low-resolution images so that they can be projected.
Tufte acknowledges that PowerPoint is a good way to present images that should be accompanied by data on a paper handout. He admits this in his essay The Cognitive Style of PowerPoint in which he gives some excellent advice about how to improve presentations. These suggestions largely involve minimizing the amount of control you allow PowerPoint to have in organizing and presenting your information. He also mentions one of the single most important pieces of advice ever offered to a speaker: Never read your slides aloud.