A large-scale study was designed to assess the extent of emotional disturbance among Head Start children and to provide a consistent basis for selection if therapeutic intervention were indicated. The study's aim was to avoid the problem of shifting baselines by individual teachers for determining the degree to which their children were departing from normalcy and the tolerance limits they were willing to accept before assigning a child to therapeutic treatment. A total of 413 children were tested using Kohn's Behavior Checklist and Competence Scale to assess their overt functioning in group settings. The study seems to support the usefulness of this instrument and procedure for identifying, at an early age, children who are later likely to have severe problems. The question of whether therapeutic intervention with this population can have an appreciable impact on changing this prediction was the subject of a subsequent study. An examiner's manual for the Behavior Checklist and Competence Scale is included in this report. (LH)