The Classroom Attitude Observation Schedule was developed and field tested for study of independent child behavior in the open classroom. Eight Head Start classrooms were used for field testing, six of which used the Tucson Early Education Model curriculum and two of which, for comparison, used local curricula. Procedures involved observing and recording into mutually exclusive activity categories the location of children and adults at two-minute intervals over a thirty-six minute free-choice period. Incidents of inappropriate behavior were also recorded. During the middle twelve minutes, all adults except the observer left the classroom. The procedure demonstrated sensitivity to changes in child behavior during teacher absence. Comparison classrooms had significantly more incidents of inappropriate behavior during teacher absence than during teacher presence. TEEM classrooms maintained a stable pattern of behavior throughout the observation period. The system was concluded to be extremely useful in assessment of independent learning behavior of children in large groups and should transfer easily to other open classroom settings. (Author/KM)