This article reports the technical quality of a measure describing the quality of classroom assignments piloted in the Los Angeles Unified School District's proposed new accountability system. For this study, 181 teachers were sampled from 35 schools selected at random. Participating teachers submitted three language arts assignments with samples of student work (N = 50). Results indicated a fair level of agreement among the raters who scored the assignments and a high level of internal consistency within each dimension of assignment quality. Results presented a mixed picture with regard to the stability of the ratings at the different levels of schooling and the number of assignments needed to yield a consistent estimate of quality. However, secondary students who received higher quality assignments produced higher quality written work and scored higher as a group on the reading and language portions of the Stanford Achievement Test, 9th edition (Stanford 9) adjusted for student background and prior achievement.