The IB Diploma Programme includes six subject areas; an extended essay of 4,000 words; experiential learning through creativity, action, service (CAS); and theory of knowledge (TOK), a course that fosters critical thinking. Assessment in each of the six subject areas is based on student performance against set standards rather than each student’s position in the overall class ranking. External assessments include a variety of tasks that emphasize higher-order cognitive skills and may take the form of written essays and examinations. Internal assessments, marked by teachers and moderated by the IB, are factored in to the students’ final grade.