Friday, March 5, 2010
Missing the (Power)Point
In his Manner of Speaking blog on February 25th, John Zimmer discussed Power Point Math: When in Rome, do as the Romans do. His post illustrates how to miss the point - how NOT to discuss large numbers in a presentation.
John begins by mentioning two statistics about PowerPoint presentations from the eighth slide in a BBC magazine article. These originally were that:
“Businesses globally make an estimated 30 million PowerPoint presentations each day.”
“The average PowerPoint session runs for 250 minutes, from startup to shutdown.”
Then he proceeds to ignore both statistics. (Why would you do that to your audience?) Instead he assumes that there are 1 million presentations given per day, and that the average presentation runs for 1 hour. He adds an additional assumption that:
“…the average PowerPoint presentation involves 15 people (audience, presenter and technicians all included).”
John multiplies, and finds that there are 15 million hours of people’s time each day spent watching PowerPoint presentations. Then he divides that number by 8760 to convert from hours to years, and arrives at a figure of 1712 years. He notes that the Roman Empire didn’t last that long.
My high school chemistry teacher used to emphasize dimensional analysis - that you always need to watch the units attached to numbers that you calculate. If we take the 15 million man-hours per day and divide by 24 (hours in a day), the result is 625,000 men. That’s more like holiday audience for the Pope than the life span of the Roman Empire!
Let’s go back to the two quoted statistics. 250 minutes (or 4.166 hours) actually is the average time spent by a man for preparing a PowerPoint presentation, so when we multiply by 30 million per day we arrive at a larger figure of 125,000,000 man hours per day. What does that really mean?
Let’s put it into a global perspective. According to the US Census bureau, the 2010 world population is about 6,831,000,000 people. Assuming that we put everybody to work for 8 hours per day, there potentially could be 54,648,000,000 man-hours available per day. So, we would only be consuming 0.23% of that global effort in preparing presentations.
Another perspective could compare how preparing PowerPoint stacks up relative to building something truly exceptional. The Great Pyramid of Khufu at Giza took about 1,150,100,000 man hours (or 131,200 man-years) to build, so just preparing presentations each day takes about a ninth of a Pyramid.
Still another perspective could come from converting man-hours into dollars. Back in 2003 Dave Paradi estimated that 15 million man hours per day really was just the wasted effort due to PowerPoint, or $252 million dollars per day. In a comment on John’s post I referred to Dave’s estimate. Max Atkinson also commented that he had calculated the annual waste in the UK. Shouldn’t we be more interested in the waste rather than the total?
A more complete estimate really should consider the time spent (or wasted) per day both in preparing and in watching presentations.
The Great Pyramid image on Wikimedia Commons is from Nina Aldin Thune.