Over the holidays, DCPS sent letters to parents notifying them if an “unqualified” teacher was teaching their children, resulting in a series of complaints and bureaucratic messes. For example, parents were asked to log into the DCPS website to get the names of the teachers, but those who logged in found their children’s teachers from the previous academic year. A number of teachers objected, noting that they had been incorrectly listed as “unqualified.” The letters also raised a sticky question: what does “qualified” even mean?

The federal “No Child Left Behind” law mandates “highly qualified” teachers—someone who has a state teacher’s license and bachelor’s degree in the subject in which they teach, and who has passed a subject-area test. Last week, the Post reported that 800 DCPS teachers are currently deemed “unqualified” under NCLB, down from nearly 1200 last year.

But there are a number of caveats. New teachers, like those who enter through the D.C. Teaching Fellows or Teach for America, teach with three-year provisional licenses while simultaneously earning masters degrees in teaching. Staffing shortages can cause teachers to teach courses outside of their subject-areas (for example, a physics teacher teaching geometry). Other teachers are given grace periods during which to earn their certifications.

These factors inflate the number of “unqualified” teachers, raising alarm without giving parents much real information about whether or not their child’s teacher is any good. What’s more, teachers who remain unqualified can be terminated. (Candi Peterson, a board member of the Washington Teachers’ Union, recently blogged in anger over the prospect of 800 teachers being fired for this reason. However, Ms. Peterson’s numbers are a bit exaggerated. Last year, according to the Post, 1,187 teachers were “unqualified” but only around 250 were fired for failing to obtain certification within extended deadlines.)