This report examined the extent to which student attendance, teacher certification, and teacher absence explained differences in reading and mathematics achievement among elementary and middle schools in New York City (beyond that explained by such student demographics as receiving free lunch, being an English language learner, and receiving special education services). Multiple regression analysis indicated that student attendance and teacher certification rates were positively and significantly related to student outcomes on mathematics and reading achievement tests, even after factoring out the effects of student demographics. However, average teacher attendance had no significant effects. These results were obtained for both elementary and middle schools. The effect of student attendance was greater than that for percentage of certified teachers in middle schools, but not in elementary schools, where the effects were of the same magnitude. (SM)