The Assessments of Performance in Teaching (APT) is a classroom teacher performance evaluation procedure mandated by the South Carolina legislature for all student and first year teachers. Aiming to measure minimal competence, the instrument addresses five performance dimensions: planning, instruction, class management, communication, and attitude. Over 1600 teachers were observed 3 times and rated on the 5 performance dimensions with from 8 to 11 indicators each. Objectivity has been substantiated using three observers with the same teaching demonstration. Internal consistency is high and performance dimension correlations with the total instrument score are all significant. Construct validity studies indicate that the APT is useful for multidimensional assessment of teacher skills and behavior. A latent trait analysis of these data suggests an overall unidimensional series. The tentative standards used for research purposes indicate that approximately 10 percent of the sample teachers would not be considered minimally competent. These findings will be used to design the final version of the APT to be implemented in July 1982. (PN)