A recent series of studies suggests that teacher absences have a negative effect on student achievement and district finances.
Raegen T. Miller, Richard J. Murnane, and John B. Willett. (2008).
Do Teacher Absences Impact Student Achievement? Longitudinal Evidence from One Urban School District. NBER Working Paper No. W13356
Charles T. Clotfelter, Helen F. Ladd, and Jacob L. Vigdor. (2007). Are Teacher Absences Worth Worrying About in the U.S.? NBER Working Paper No. W13648