However, the survey method does provide information about issues (especially perceptions) that could not be obtained through other methods. In addition, the TALIS Video Study will provide important perspectives on the validity of self-report data because it will collect both survey and video data. Because the database does not allow identification of classrooms, it is not possible to link teachers with their class students. Student outcomes can, therefore, be associated only with the school-aggregated indicator of teachers. That review argued for better national and international information on teachers. These were attracting, developing, and retaining effective teachers; school policies and effectiveness; and quality teachers and teaching.