Wednesday, April 8, 2009
Ninth grade is always Kentucky's largest grade. The graph above is one illustration, tracking one class through six years of testing. There, you see almost 3,000 more students in grade 9 than in any other grade. Our public schools retain more students in that grade than any other, producing a dramatic bulge in total students.
From the graph, I could say, "Out of every 100 ninth graders tested, 82 made it to twelfth grade testing four years later."
I could also say "Out of every 100 seventh graders in spring testing, 88 made it to twelfth grade testing six years later."
Looking at the graph, you can see why the two results are different, and how the giant helping of retained students makes the problem look much worse.
Here's the thing.
A common approach to describing graduation rates begins with the phrase "out of every 100 ninth graders...." That means "We divided graduates by ninth graders." It also means "We included a bunch of ninth graders in this year's math that we also included in last year's math." It means "We're doing a double count."
No matter how many years a student spends in grade nine, that student can only collect one high school diploma.
The method that simply divides by ninth graders is simply wrong. If you hear numbers presented that way, I urge you to ask how many times they count repeating ninth graders.
We have a big enough problem with the students we really lose, without claiming that we lose even more.
Two small added notes. First, thanks to Steve Clements for questioning me about graduation issues this weekend: his thoughts led to this post. Second, I said above that the same bulge happens every year. The numbers are below, and a PDF graphed version is here.
Update: the numbers above use a fall count of grade 12 for the classes of 2007 and 2008, and a spring count for earlier years. I've added a new post here that shows spring counts consistently, allowing a better comparison over time.