Be Wary Of Statistics

While watching the Olympic recap this morning, the sportscaster mentioned that the U.S. men’s basketball team struggled shooting the 3-point shot. I punched up the box score for the game, and, sure enough, the team did struggle making only 5 of 21 shots (23.8%). Then I looked at the individual player shooting percentages and saw that Kobe Bryant made 0 of his 8 3-pointers, which means the rest of the team made 5 of 13 (38.5%). This is close to the average of 40% that all teams average. In reality, one player shot rather poorly while the rest of the team shot at an average clip.

This reminded me of an attendance presentation given to our staff last year. We were being given a long, long lecture about our inability to take attendance and were threatened with returning to a more labor intensive method of attendance submission.

The PowerPoint slide showed the number of periods when attendance was not taken on a week by week basis, which obviously looked quite startling to see numbers as high as 60 in a week. However, when I started working the numbers out a bit I found that the slide was indicating that 4-8% of the entire staff did not take attendance on a given day, including substitutes in the building. In other words, 6-10 people on a given day did not take attendance, and some of these 6-10 people were substitutes.

When I raised my hand and pointed this out after over 30 minutes of presentation time, that 95% of the teachers receiving this lecture had no problem submitting attendance properly and that the administration could take this up with the individual teachers rather than lecturing everyone, I was met with a cold stare. However, my words did highlight how the numbers used in the presentation were somewhat misleading and were meant to shock.

Mark Twain (among others) once said, “There are three kinds of lies: lies, damn lies, and statistics.” Be wary of statistics.