This study investigates whether adequate yearly progress (AYP) status, locale, and sector--common variables used to judge the quality of schools--accurately signal true differences in instructional practices in high school mathematics and science. Using data from the High School Longitudinal Study (HSLS), we find the school-to-school variation in instructional practices to be minimal. Controlling for a variety of school and teacher characteristics, we find that there is no difference in the use of developmental instruction between schools that make AYP and schools that do not, urban and nonurban schools, and public and private schools.