The incremental validity of two high-inference, multiple-dimension measures of student and teacher perceptions of their school environment was investigated. Incremental validity was described as accounting for increasing amounts of criterion variance (average daily attendance and achievement on the Iowa Tests of Basic Skills) with a set of independent variables, using multiple regression analysis. The two instruments--the School Survey and My School Inventory--were administered to 1,018 elementary school teachers and 6,151 fourth grade students, respectively. Teacher perceptions of the school's educational effectiveness were strongly correlated with achievement. Positive teacher perceptions of special services programs, relationship with the principal, and relationships with colleagues were also associated with variance in achievement. Teacher perceptions of school effectiveness were also highly correlated with average daily attendance. Student perceptions of school academic difficulty were strongly and negatively correlated with achievement. Attendance was correlated with students' positive perception of cohesiveness among peers. Although both tests appeared to have incremental validity, for the achievement criterion; validity was higher with the School Survey, which was used to measure teacher attitudes. This finding is of considerable importance because previous studies with similar paradigms have focused on student attitudes. (GDC)