Telling the Story

Hypnotizing Chickens

A recent New York Times article about how PowerPoint presentations are a major problem in the military contains an example of an actual PowerPoint slide used last summer in Kabul meant to portray the complexity of American military strategy.  The slide is so comical, it’s gone viral on the internet.

The problem has gotten so severe that some military officers have gone so far as to ban the PowerPoint application entirely.  Thomas Hammes, a retired Marine colonel, referred to news media sessions using PowerPoint slides as so mind-numbing that it is like “hypnotizing chickens.”

And comedians are getting in on the act as seen here in this wildly popular stand up routine. http://www.youtube.com/watch?v=ORxFwBR4smE&feature=player_embedded

Even Dr. Edward Tufte of Yale University, an expert on information presentation who has participated in the accident investigation of both Space Shuttles, wrote extensively on the misuse of PowerPoint slides in NASA during the accident investigation board.

I once sat in a district-wide, start-of-school-year meeting in which the presenter (with a Ph.D. behind her name) told us how to make classroom learning more interesting.  She presented her material using PowerPoint and read it to us verbatim. Talk about irony!

But aren’t we blaming the instrument, instead of the conductor? PowerPoint isn’t what’s broken; what’s broken is how we use it.  PowerPoint is a tool, and when used effectively, can be valuable in communicating your message, whether that message be in the form of charts, words, images, diagrams, etc.  How?  First, identify your audience. Tailor your message to speak to them.  Be creative, and that doesn’t mean using animation so your slide does cartwheels across the screen. It does mean thinking about the best way to communicate the information.  It could very well be a chart, a table, or list; it could be a diagram, or just text.   PowerPoint is not providing the message -- you are.   Don’t use it if it doesn’t help you communicate something better than you can do alone.  PowerPoint is meant to assist in the presentation, not BE the presentation.

Comparing Apples to Apples

A recent article in the Business section of the New York Times referenced a chart which compared recommended nutrition servings to federal subsidies.  

 

http://economix.blogs.nytimes.com/2010/03/09/why-a-big-mac-costs-less-than-a-salad/

 

 

(PCRM)

 

At first glance this chart appears to show a severe imbalance between nutritional needs and federal subsidies of the food industry. But upon closer examination, I found numerous issues with the way information was presented in the chart.

1. The pyramid on the left is an attempt to represent a percentage of food subsidy dollars. The largest percentage of food subsidy dollars go to meat and dairy, claiming 73.8% of the subsidy Assuming these numbers are accurate, the use of a three-dimensional pyramid leads to a skewed representation of the data. The meat/dairy slice, for example, is approximately 73.8% of the height of the pyramid. However, since a pyramid is three-dimensional, the reader is drawn to the height of each slice, but the overall volume (size) of each slice. A slice which is 73.8% of the height of the pyramid (starting from the bottom) actually takes up over 95% of the volume of the pyramid, thus lending the visual impression that the meat/dairy subsidy is significantly larger than it actually is.

 

The pyramid on the right side of the chart (recommended servings) puts the protein category near the top of the pyramid, thus reversing the effect. The two pyramids, each with their own exaggerations, combine to create a highly distorted message.

 

2) The pyramid shape also conveys a relationship beyond that of simple  size differences.   Pyramids are most often used to indicate some level of dependency - that things on the top of the pyramid are somehow dependent on the things at the bottom.  That is why we tend to  
resort to construction terms and refer to the bottom as the foundation.   (I never liked the old "food pyramid" for this same reason. You need all those foods).

3) Finally, in the chart on the left, what does a "percent" actually  mean?   Does it mean that 73.8% of the cost of meat is subsidized, or  does it mean that 73.8% of the subsidy dollars go to meat (as I suggested above)?   The  difference is important because the cost of producing meat is not the same as the cost of producing grains. Since grains are actually used to feed cattle, it is possible that some of the meat subsidy dollars actually ends up subsidizing grains (ranchers need to purchase grain to feed the cows).

By putting those two pyramids side by side, the suggestion is that one serving of meat or dairy is somehow equivalent to one serving of say, vegetables, and also that the cost of producing a serving of each is roughly the same.  Of course, that is not true - meats and vegetables  
provide for different nutritional needs, the cost of producing them is  different, and both are important to your health.

To do a true comparison, you would first need to choose a format that did not imply dependencies.  Then, to be truly fair, you would need to  somehow normalize the subsidy side to deal with factors such as  differences in cost to produce, nutrition density (you get all the  
protein you need in only 6 servings, but it takes 11 servings of  grains to give you what you need, etc.)

 

It's tempting to enhance the appearance of your charts through effects such as 3-D models, but you have to be careful that the use of such effects does not distort the information you are attempting to display.