Abstract: | This article studies the impact of teacher absences on education. Using data spanning three academic years about 285 teachers and 8,631 predominantly economically disadvantaged students from a United States urban school district, it tests assumptions that a substantial portion of teachers' absences is discretionary and that these absences reduce productivity – students' mathematics scores. Since absent teachers are typically replaced by less qualified substitutes, instructional intensity and consistency may decline: ten days of teacher absence reduce students' achievement score by about 3.3 per cent of a standard deviation – enough to lower some students' designation in the state proficiency system and, thus, their motivation to succeed. |