The Center for American Progress has a new report out on teacher absenteeism. Author Raegan Miller culled data from a large, unnamed, northern school district over a four-year period and found that on any given day one in 20 teachers was absent. Add those teacher absences up over a child's 13+ years of school and it amounts to two-thirds of a school year when Ms. Nelson is missing.

Surely some of those sick days are simply a result of being around germy kids day in and day out, but Miller found some interesting patterns that suggest there are other factors at play. Teacher absences are highest on Mondays and Fridays and tend to increase as the school year progresses.

So how can schools make a dent in teacher absenteeism? Though policy changes are certainly part of the picture (less leave available, bonuses for good attendance) teacher absenteeism seems more to do with school culture. Schools where teachers have to report their absences to a supervisor rather than to an automated system have better attendance. Teacher absences are often a symptom of other problems in the school. When student attendance increases, teacher attendance also increases.