Look Out Below!

Here's a number you are going to see bandied about in the next few weeks, purporting to show how public schools are failing. Supposedly, only 75.5 percent of 9th graders in 2005-06 graduated from high school in 2008-09. That's the latest "averaged high school graduation rate," according to a new report released by the National Center for Education Statistics. By state the statistic varies from a high of 90.7 percent in Wisconsin to a low of 56.3 percent in Nevada.

Don't believe it. The first sign that this is a bogus measure is its tortured name. The second sign of bogosity is that the rate doesn't match reality--it is far below the 89.9 percent of 16-to-24-year-olds who actually have a high school diploma or GED (see table here).

The third sign that the "averaged high school graduation rate" is bogus is the methodology behind it, invented by morons. The rate is calculated by taking the number of high school graduates in a school district in a given year and dividing by the number of freshmen in the school district four years earlier. So, any student who moves out of a school district is counted as a dropout. That's why states with little migration have high "graduation" rates, and states with lots of migration have low "graduation" rates. Pure genius.