The purpose of the assessment described in this paper was to evaluate the extent to which students could demonstrate the knowledge, skills, and attitudes detailed in the British Columbia social studies curriculum. The paper focuses on those aspects of the assessment that concerned critical thinking skills. All students in grades 4, 7, and 10 took part in the assessment; this numbered about 110,000 students. The assessment involved attitude scales, demographic questions, and two types of achievement items--multiple choice questions and open-ended activities. In addition, a questionnaire was distributed to social studies teachers; among other questions, the teachers were asked about the importance of critical thinking the their classrooms. The findings of the assessment led to the conclusions that the critical thinking dimensions of the social studies curriculum have not been as effectively implemented as intended. Six recommendations are made in the following areas: classroom practice, critical thinking, curriculum content, curriculum guidelines, implementation and in-service, and teacher education and certification. A 9-item list of references, a sample of instruments used in the assessment, and sample student answers, are included. (DB)