The purpose of this study was to investigate the degree of accuracy of teachers of educable mentally retarded (EMR) students in making estimates about student performance in reading and mathematics and to examine certain variables which may assist in explaining the variance in accuracy: sex of the student, subject area of the estimate, years teaching experience, and length of student/teacher contact time. A secondary purpose was to examine the categories of information about the student which teachers felt were important in making judgments.

The sample consisted of 28 EMR teachers and 136 (EMR) students (CA=6-13 years) from six school districts in Virginia. The teachers made estimates about whether or not students would complete 10 performance objectives in reading and 10 performance in mathematics. These estimates were then compared to the actual performances of the students as measured by the Brigance Diagnostic Inventory of Early Development. Teachers also indicated which information sources they utilized in making the estimates and in writing the students' individualized education programs (IEPs). The data were collected during individual interviews conducted by the researcher during the teacher's workday. The data were analyzed by employing a two-way analysis of variance, product moment correlations, and chi square procedures.

It was concluded that EMR teachers are good estimators of student performance regardless of the sex of the student or the subject area of the estimate. Furthermore, teacher accuracy is not related to the number of years teaching experience of the teacher or to the amount of student/teacher contact time experienced before the estimate is made. In addition, the number of information sources used by the teacher in making the estimate does not affect the teacher's ability to estimate student performance. Teachers were able to make accurate estimates based on information obtained through classroom procedures without information from more formalized procedures such as intelligence and achievement tests and psychological reports.