High school graduation rates always come up in the news. People are worried about them. People decry how low they are. People celebrate when they improve. Short of test scores, graduation rates are probably the most used indicator of educational success/failure in this country.
It makes sense to worry about graduation rates, but they're far from perfect. Two of the biggest problems are that it's almost impossible to calculate an exact rate for a school and that everybody calculates graduation rates differently.
I first learned about this a couple years ago when some folks from RAND did a study for Pittsburgh on their graduation rates. All calculations of graduation rates start with the same statistic: the number of new freshman who enroll in a given year. But how do we determine how many of these people have graduated and what the graduation rate should be? Do we check on them after four years? 5? 6? What about students who move out of the district? What about students who move into the district or otherwise enroll after the start of 9th grade? What about people who just stop showing up -- how do we know if they dropped out, moved away, or something else? Can we tell which students are in the 9th grade for the first time and which ones are repeating?
A large part of the difficulty is that there is no national database of students. If a student leaves and enrolls in a different city or state, there's no firm way of knowing that they're still enrolled. Similarly, if a student simply stops showing up at school rather than declaring themselves a dropout it's hard to tell if they've dropped out or enrolled in another district.
Anyway, the point is that it's not possible to compute an exact graduation rate. And the fact that every state and district seem to use different formulas means that it's hard to compare these inexact numbers. But, apparently, the Dept. of Ed. is going to step in and standardize the way that graduation rates are calculated. An article in the NY Times today says that the details of the new formula have not been released, but that all states will be required to use the same one.
The technicalities of which formula a state uses seems so trivial and boring that most people probably don't really give it much thought. But the article details people reacting quite strongly to the announcement. This makes sense because although the change is small, the effects of the change might be huge. The federal govt. is ostensibly holding states accountable for graduation rates, but they all calculate them differently (a recent change in North Carolina's formula led the official rate to drop from 95% to 68%). Sometimes the smallest changes are the ones that matter most.