As the old adage goes, you never get a second chance to make a first impression. That's the premise of a recent study by economist Michael Hansen (a finalist in NCTQ's 2009 research competition). Using 14 years worth of data from North Carolina, Hansen looks at attendance patterns and finds that the amount of sick leave teachers take in any given year varies throughout their career in rather predictable ways.

Teacher absences are lowest at two points: in a teacher's first year in a school and when a new principal comes on board.

Absences increase in a teacher's last year of employment in a school--with most absences concentrated in the second half of the year, particularly if a teacher leaves the state (which most likely means that the teacher is leaving teaching entirely).

Targeting incentives, says Hansen, like a cash bonus for unused days at the end of the year, might help reduce the peaks in absences. About 20 of the 100 districts in the Tr3 database offer such bonuses (far more common are buy-backs paid out at retirement for any unused leave), but the effectiveness of such plans is largely unknown.